Nanocarbon electrochemistry and interfaces II

Resume : Conductive Boron Doped Diamond (BDD) is known as an outstanding electrode material exhibiting a wide electrochemical potential window in aqueous electrolytes (>3V), high chemical stability in harsh environments and/or at high voltage/current densities, chemical inertness, biocompatibility and low background/capacitive currents. However, BDD exhibits a relatively poor surface catalytic behavior. We overcame this issue by immobilizing catalysts at the electrode surface using transition metal nanoparticles. Toward this goal, the reactivity of the BDD electrodes was enhanced using transition metals such as platinum, iridium, gold, ruthenium, etc and their corresponding alloys. Their characteristics in terms of size, oxidation levels, and adhesion were well characterized to ensure high stability and reproducibility. These nanoparticles exhibit an interesting electro-catalytic activity and open the way to the detection of products derived from enzymatic reactions, pesticides or many other electrochemically non-active species. We propose a complete multi-sensor detection system based on several BDD electrodes each functionalized using a different catalyst metal in the form of nanoparticles, thus each exhibiting a specific reactivity, enabling the recording of chemical fingerprints of the products to detect in real samples. An advanced algorithmic learning / recognition methods enables the system to behave as an ?electronic tongue?. The approach was applied to several case studies, including hydrogen peroxide, food contaminants such as scatol or indole, nitrate/nitrite pollution of water sources and industrial sites and even much more complex systems such as coffee brands!

Resume : Electrochemical activity of the carbon materials is significantly influenced by surface functional groups. For example, electrochemical pretreatment of carbon electrode drastically increases surface oxygen functional group and improves electrochemical activity for various biochemicals such as catecholamines and L-ascorbic acid. We have been developing nanocarbon film electrodes by using electron cyclotron resonance (ECR) or unbalanced magnetron (UBM) sputtering techniques. The films shows wide potential window because of hybrid structure of sp2 and sp3 bonds and low capacitive current due to very flat surface. We recently prepared nitrogen terminated carbon (NS-UBM) film by ammonia gas treatment after depositing the film by UBM sputtering and compared its electrochemical performances with those of a nitrogen containing carbon (N-UBM) film also deposited by UBM sputtering in the presence of nitrogen gas. The nitrogen concentrations on the surface of both films are almost identical, which is confirmed by XPS measurement. The oxygen reduction at NS-UBM film shifts more positive compared with N-UBM film electrode, suggesting that surface groups are very important to reduce overotential for oxygen reduction. The peak potentials and heights of some redox biomolecules are also compared using above two films. In contrast, a fluorinated nanocarbon (F-nanocarbon) film can be formed by CF4 plasma treatment of pure carbon films. The potential window of the film increases from 3.7 V to 4.1 V and surface capacitance drastically decreased after fluorination This F-nanocarbon film electrode shows much better stability compared with fluorinated GC electrode against repetitive potential cycling. The F-nanocarbon film electrode shows reversible electrochemical reaction of a ferrocene based mediator while strongly suppressing the electrochemical oxidation of Fe2+ due to hydrophobicity of F-nanocarbon surface. This selectivity provided the current amplification of ferrocene mediators with Fe2+ ions by using the F-nanocarbon film electrode without interference from direct oxidation of Fe2+ ions. This system was applied to realize lipopolysaccharide (LPS) biosensor by modifying the F-nanocarbon surface with polymer film to adsorb LPS. After preconcentration of LPS onto the polymer surface, we applied ferrocene labelled polymyxin B to LPS because polymyxin-B strongly recognized LPS. Finally, we detected LPS concentration by selective electrochemical signal amplification.. Since the direct electrochemical oxidation of Fe2+ was almost completely suppressed on the F-nanocarbon film, we can obtained large current amplification by applying high concentration of Fe2+. As a results, the F-nanocarbon film based LPS biosensor shows better linearity particularly at low concentration region due to the suppression of direct Fe2+ oxidation. As a result, the detection limit of 2 ng /ml was obtained. Another application of F-nanocarbon film is to detect lipophilic antioxidant such as??-tocophenol (Vitamin E) quantitatively in bicontinuous microemulsions (BMEs). BMEs, in which water and oil phases coexist bicontinuously on a microscopic scale, can dissolve hydrophilic, lipophilic and amphiphilic compound simultaneously. Electrochemical contact with water or oil solution phases in a BME can be alternatively changed by controlling the hydrophilicity and lipophilicity of the electrode surface. We tried to detect lipophilic and hydrophilic antioxidant selectively using mixed solution of 1 mM ascorbic acid and 1 mM ??tocophenol using indium thin oxide (ITO) and F-nanocarbon electrode. On the hydrophilic ITO electrode, the oxidation peak of L-ascorbic acid was observed even in the presence of ??tocophenol. In contrast, only the peak of ??tocophenol was observed at F-nanocarbon film electrode. This indicates that F-nanocarbon film selectively detect lipophilic antioxidant in the BMEs because only oil phase containing ??tocophenol is contact phase on the F-nanocarbon film electrodes. This BME-EC technique can applied for quantitative analysis of antioxidants in olive oils and exhibited a reliable and good performance that are comparable with conventional instrumental analysis. The lack of an extraction step in our method is a major improvement compared with other assays.

Resume : Graphene has attracted much attention as a chemical sensor material because of its high sensitivity to surface adsorbates. Decoration of Pd nanoparticles on graphene has been widely used to acquire hydrogen sensitivity. However, effects of gate-induce electric field on sensitivity of Pd nanoparticles decorated graphene (Pd-Gr) have not yet been fully investigated. In this work, sensitivity enhancement of Pd-Gr induced by gate electric field is experimentally and numerically demonstrated. Gate voltage dependence of hydrogen sensitivity or current change between drain current with and without hydrogen were measured. Obtained hydrogen sensitivity is much higher in the electron conduction than in the hole conduction. The sensitivity difference between electron and hole conduction regimes in Pd-Gr was numerically analyzed by non-equilibrium Green function calculations. The decoration of Pd nanoparticles causes the local hole doping to graphene. This local hole doping disturbs electron transport more severely than hole transport, because p-type region originated from local hole doping acts as a potential barrier for electron. When hydrogen is introduced, adsorbed hydrogen atoms generate dipoles at the surface of Pd nanoparticles. These dipoles compensate the local hole doping caused by Pd nanoparticles, and thus the degraded electron transport is recovered, resulting in the higher hydrogen sensitivity in the electron conduction.

Resume : Human breath contains a lot of volatile organic compounds (VOCs). Since VOCs are potential markers of diseases, gas sensors targeting VOCs have attracted great attention. Graphene is composed of six-membered ring structures; graphene strongly captures aromatic compounds with ?-? interaction. Furthermore, graphene has high surface-to-volume ratio. These properties make graphene a promising material for selective and sensitive sensing of aromatic compounds. However, sensing properties of graphene for VOCs other than aromatic compounds have not yet been fully explored. In this study, sensing properties of Pt-functionalized graphene for aliphatic alcohol were investigated. Sensor was measured at temperatures ranging from room temperature to 200 °C. To evaluate gas detection capability of the sensor, hydrogen and ethanol were used. We confirmed that Pt functionalization enhanced sensitivity to both hydrogen and ethanol. Sensitivity of hydrogen did not show temperature dependence, while ethanol showed higher sensitivity as temperature increases. This is considered to be due to an increased decomposition of hydroxyl group by Pt catalysis and greater hydrogen release at higher temperatures. Then, we measured alcohols with different numbers of carbons. Although concentration was constant, sensitivity increases as the number of carbon atoms of the alkyl chain. This probably arises from a greater adsorption of longer alkyl chain to graphene because of stronger hydrophobic interactions.

Resume : added into UV-curable polyurethanes to form flexible conductive coating on PET plate via spin-coating and UV exposure. The microstructure of composite and coatings were investigated by TEM and SEM. The coatings were stripped from PET plate and assembled as humidity sensor. The sensor exhibited superior humidity sensing properties with wide response range(0.15%-69.52%), short response/recovery time(32s/54s), excellent repeatability and flexibility. The resistance of sensors is nearly invariable after 200 folding times. The results demonstrated the has the potential application to humidity sensors.

Resume : The electrochemical properties of graphene, and related 2D materials (notably MoS2), will be discussed. Electrochemical methods can be used to prepare, and to functionalise , these materials. We will discuss our recent work on the development of a simultaneous exfoliation/functionalisation strategy. We will also discuss how such functionalised materials can be used to optimise performance of 2d materials in the context of electrochemical energy storage.

Resume : The efficient storage and supply of energy from renewable resources is a worldwide challenge and requires efficient and fast energy storage devices. Technologies such as lithium ion and other battery systems are already widespread. Carbon materials are another promising class of materials for energy storage, e.g. in batteries and supercapacitors. Another important area of research is the generation of solar fuels using benign and readily available catalysts for the transformation e.g. of carbon dioxide into useful chemicals and building blocks. Here we report on the production, characterization of surface functionalized nanodiamond of different origin. The resulting nanodiamond derivatives can be used as additives in supercapacitor materials, as heterogenized organocatalysts as well as for the photocatalytic generation of solar fuels. Challenges such as the stable surface modification and the agglomeration of nanoparticles will be addressed. This project has received funding from the European Union's Horizon2020 research and innovation programme under Grant Agreement no. 665085 and the "Bayerisches Staatsministerium für Umwelt und Verbraucherschutz? in the network UMWELTnanoTECH (http://www.umwelt-nanotech.de).

Resume : While boron-doped diamond (BDD) and TiO2 have been recognized as attractive electrodes and photo-catalytic materials, the composite films consisting of TiO2 and BDD are potential (photo)electrode materials for various applications. On these electrodes, a so-called advanced oxidation process, namely the creation of highly active oxidants or radicals is expected, resulting in the rapid and efficient decomposition of aqueous organics and contaminants. However, the growth and electrochemical applications of such kind of composite films are seldom reported in the literature, partly due to the difficulties of material preparation. In this presentation, we introduce a novel approach to synthesize TiO2/BDD composite films. plasma electrolytic oxidation (PEO) is combined with microwave-assisted chemical vapor deposition (MWCVD) technique for the growth of these films. The investigation of the formation of porous TiO2 film on the Ti substrate and the overgrowth of TiO2 with BDD films will be shown. The achievement of different phase compositions (the varied ratios of TiO2 to BDD on the surface) by altering CVD growth time will be presented. The characterization of the surface morphology and chemical compositions of as-prepared samples with scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy will be summarized. The application of Rockwell C indentation to examine their mechanical properties will be presented. The SEM images reveal full filling of TiO2 pores with BDD. Compare to direct deposition on substrates, a better adhesion strength is found between diamond and metal substrate after PEO pretreatment. The formed TiO2 interlayers are expected to reduce the diffusion of carbon species and the formation of TiH2 phase, eventually causing the embitterment of Ti substrates and leading to the reduction of the mechanical performance. The investigation of electrochemical properties of these composite films with respect to potential windows, electrochemical activity, and capacitance will be summarized. Their potential applications in the fields of electrochemical capacitors and photoelectrochemistry will be shown and discussed.

Resume : Abundance and low-cost materials with high electrochemical catalytic activity for oxygen reduction reaction (ORR) are in urgent demand for energy storage and conversion devices. In this work, an efficient ORR electrocatalyst of Pt-decorated three dimensional N-doped carbon microspherical cavity (Pt-N/C) for advanced ORR catalyst by using polystyrene (PS) as template and dopamine as a single precursor. Electrochemical characterizations showed good performance of Pt-N/C including excellent ORR catalytic activity, remarkable methanol tolerance and good durability in alkaline solutions. It revealed that the numerous Pt nanoparticles strongly decorated on carbonous substrate coupling with the doped nitrogen synergistically allowed to the advanced catalytic activity, while the unique 3D microspherical porous morphology facilitated the oxygen adsorption and mass transfer. Importantly, the strong Pt-C interaction due to the powerful adhesive capability of dopamine effectively reduced the amount of Pt and provided better mass activity (MA) and specific activity (SA) than the commercial Pt/C electrocatalyst. This work provided a strategy for designing advanced Pt-based ORR catalyst with good performance and high MA.

Resume : The study investigated the properties of biochar and its potential in chlorobenzene degradation. Biochar was derived from rice husk and charred at 550? in N2 atmosphere, which showed a significant degradation of chlorobenzene in ambient atmosphere. The results from Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and Raman spectroscopy (Raman) indicated the formation of poorly ordered graphene stacks embedded in amorphous phases on biochar. Fourier Transform Infrared Spectroscopy (FTIR) and Electron Paramagnetic Resonance (EPR) suggested that hydroquinone-quinone moieties existed on biochar, which could induce the generation of reactive oxygen species (ROS) and promote degradation of chlorobenzene. Furthermore, hydrogen peroxide and hydroxyl radicals were generated from the reduction of oxygen with the oxidization of phenolic hydroxyl groups on biochar, which was responsible for chlorobenzene degradation. In addition, more types of intermediate products were discovered by biochar system compared with conventional Fenton reaction, which could be possibly ascribedto the interfacial reaction between chlorobenzene and ROS on biochar surface. The findings in this study would provide new insights into the application of biochar in pollutant removal.

Resume : Nanomaterials are nowadays at the forefront of materials science research. The design and realization of hierarchical nanoarchitectures, in which selected components are arranged to leverage their expected mechanistic functions are obtaining a wide range of applications, from the aerospace industry to bio-medicine, and as benchmarks for many catalytic reactions. Carbon-based nanomaterials have been the main actors of nanotechnology since their very first discovery, and their unique morphological/electronic properties are particularly suited to be used in electrocatalytic applications. CNTs and graphene are indeed ideal supports in catalysis as they have an optimal electronic conductivity and provide percolation routes for charge transfer reactions to occur. The integration of nanocarbons into hierarchical materials is an effective strategy to further boost the potentiality of nanostructured catalysts. The generation of multiple interfaces in such hierarchical assemblies is responsible for their exceptional activity, whose origin is however only rarely understood. We will show that, once embedded within nanoarchitectures made of multi-wall carbon nanotubes or graphene and metal oxide shells, the catalytic properties of nanoclusters (1,2) and metal nanoparticles (3,4) can be dramatically enhanced according to mechanisms which likely involve the concerted and synergic participation of all component building blocks in the electrocatalytic steps. References (1) F.M. Toma et al., Nature Chemistry 2010, 2, 826 (2) M. Quintana et al. ACS Nano 2013, 7, 811?817 (3) R. Mazzaro et al. ChemistryOpen 2015, 4, 268 ? 273 (4) G. Valenti et al. Nature Communications 2016, 7 DOI: 10.1038/ncomms13549

Resume : Understanding and controlling the growth of the vital Li2O2 product, which is associated with intrinsic property of cathode surface, is essential to design effective cathode catalysts in Li-O2 batteries. Herein we establish the correlation between the Li2O2 growth model and the O2 adsorbability on cathode surface that determines the pathway of the first electron transfer to O2. The weak O2 adsorbability drives the solution growth model to form Li2O2 toroid, while the strong one drives the surface growth model to thin film. Based on this mechanism, we select the N-doped carbon nanocages as cathode to realize a simultaneous large discharge capacity and low charge overpotential by forming copious thin-film Li2O2, deriving from its high specific surface area and enhanced O2 adsorbability due to N-doping. Our study demonstrates an effective strategy to design advanced cathode catalysts in Li?O2 batteries and potentially other metal-air batteries. Reference: ?Effect of oxygen adsorbability on the control of Li2O2 growth in Li-O2 batteries: implications for cathode catalyst design? Lyu ZY, Yang LJ, Luan YP, Wang XR, Wang LJ, Hu ZH, Lu JP, Xiao SN, Zhang F, Wang XZ, Huo FW, Huang W, Hu Z*, Chen Wei*, Nano Energy. 36, 68-75 (2017) DOI: 10.1016/j.nanoen.2017.04.022

Resume : From the past few years, carbon based nanomaterials (N-doped carbon nanotube arrays, N-doped graphene, N-doped graphene nanoplatelets, etc.) have been widely studied as highly efficient catalyst for the oxygen reduction. Recent studies on microwave assisted method demonstrate a supporting evidence for the formation of carbon quantum dots (CDs) from bio-abundant starting materials as glucose, amino acids, etc. Recently, uniform N doped CDs which shown highlighted results toward ORR were synthetized by one step solvothermal process using bottom up mechanism from N-Methyl-2-pyrrolidone. Although there have been important research focusing on the N-doped carbon dots, their use in electrocatalysis toward oxygen reduction is still scanty. Meanwhile ionic liquids and its derivatives have been started to be used as additive for oxygen reduction. In this context, we develop facile route to synthetized N-doped few nanometer scale CDs by microwave assisted method as high efficient catalyst for ORR. Our studies were demonstrated that the N-doped CDs synthetized in ionic liquid (1-ethyl-3-methylimidazolium) exhibit exceptional selectivity toward 2 electron pathway resulting production of hydrogen peroxide (95% ±2 % over a broad range of potential from 0.6 V to -0.2 V vs RHE). In addition, the N-doped CDs can be used as platform for electrocatalysis by inserting non noble metal ion (Fe, Co, Zn, etc.) or by surface functionalization.

Resume : Here, we firstly report a highly efficient dye-sensitized solar cell (DSSC) employing single layer graphene (SLG) and Poly(2,2-Dimethyl-3,4-propylenedioxythiophene) (PProDOT-Me2) nanocomposite as counter electrode (CE). To evaluate the performance of CEs, physical, electrochemical and photovoltaic analyses were conducted. The growth rate of the PProDOT-Me2 polymer increases with incorporation of SLG, introducing more densely packed surface morphology and well adherence of the film on the substrate. Furthermore, the SLG/PProDOT-Me2 nanocomposite-based CE exhibited a vigorous electrocatalytic activity in comparison with that of SLG, PProDOT-Me2 and platinum (Pt) based CEs due to its large surface area and high conductivity. As a result, the SLG/PProDOT-Me2 CE based cell achieved a conversion efficiency of 7.56%, which is considerably higher than that of the SLG (0.63%), PProDOT-Me2 (5.62%) and Pt (7.24%) under same experimental conditions. It is obvious that combining SLG and PProDOT-Me2 reduces the electron transfer resistance and improves the interface of substrate/CE, leading to an increment in photo-current (Jsc), open circuit voltage and fill factor of the cell. Moreover, besides a high conversion efficiency, SLG/PProDOT-Me2 nanocomposite-based CE offers prolonged electron lifetime, fast start/stop capability, high chemical and Jsc stabilities for the proposed DSSC. Hence, outstanding catalytic activity, high stability, facile preparation and low-cost of SLG/PProDOT-Me2 nanocomposite offer it as CE material instead of Pt for large-scale production of photovoltaic systems. Key words: PProDOT-Me2, Graphene, Electrodeposition, Dye-sensitized Solar Cell, Nanocomposites

Resume : It is well known that diamond nanoparticles' surface charges play a determining role in view of its subsequent material characteristics. Surface charges are determined by the surface functional groups present in the diamond nanoparticles, and can be controlled through different cleaning methods, annealing treatments or surface functionalization. The manipulation of these surface charges will be deeply important for a wide range of applications and will have an important influence over colour centres fluorescence. However, for most applications, diamond nanoparticles have to exhibit stability in colloidal systems to prevent particles? aggregation. The key indicator of a colloid stability is known as zeta potential and is defined as absolute zeta potential values greater than 30mV. Diamond nanoparticles usually exhibit negative zeta potentials due to oxygen based surface functional groups, but hydrogenated diamond nanoparticles were proved to have a positive zeta potential although the origin was uncertain. In this work, the positive zeta potential of commercial 50 nm size diamond nanoparticles after vacuum annealing treatments at 1000°C is explained. At this temperature, a graphitic layer is created around the diamond core of the diamond nanoparticles. Positive zeta potential in nano- structured carbons is explained due to the presence of basal planes in graphite, which leaves oxygen-free Lewis sites and so promotes the suppression of acidic functional groups. At the same time, sp2 carbon creation on diamond nanoparticles surface eases low temperature (500°C) diamond nanoparticles hydrogenation, previously demonstrated for detonation diamond (5nm).

Resume : We have recently reported that graphene sheets can be spontaneously functionalized with anthraquinone molecules in a one-pot process, during the oxidative electrochemical exfoliation of a graphite electrode in a 0.1 M H2SO4 solution containing anthraquinone diazonium ions (Carbon, 2017, 111, 83-93). Electrochemical exfoliation of graphite in only the abovementioned solution afforded graphene sheets with low oxygen content. In this talk, new results related to the characterization of the electrochemical exfoliation process will be presented. As mentioned above, graphene sheets can be functionalized during the electrochemical exfoliation process by using appropriate reagents and experimental conditions. The resulting materials were characterized by several techniques such as Fourier transform infrared, X-ray photoelectron and Raman spectroscopy, thermogravimetric analysis, elemental analysis, electronic conductivity measurements and electrochemical techniques. Recent results on both processes (electrochemical exfoliation and simultaneous functionalization during electrochemical exfoliation) will be presented.

Resume : Carbon nanofibers (CNFs) and Silicon carbide nanofibers (SiCNFs) used as the second reinforcements of carbon/carbon (C/C) composites were grown radially on the carbon fiber surface, respectively. The microstructure of SiCNFs and their effects on the interfacial structure and thermal conductivity of C/C composites were investigated. Results show that pyrocarbon (PyC) covered on CNFs is high-texture (HT) PyC, and there is a interface layer between fiber and matrix consists of middle-texture (MT) PyC and CNF HT-PyC. MT-PyC is first covered on the SiCNF surface, which is followed by HT-PyC. The interface layer between carbon fibers and matrix is composed by SiCNFs, MT-PyC and HT-PyC. These different interfacial structures are leading to the change of thermal conductivity of C/C composites in different direction. The thermal conductivity of CNF-C/C composites increases more significantly in the direction perpendicular to carbon fiber than the direction parallel to fiber. However, the thermal conductivity of SiCNF-C/C composites increases more significantly in the parallel direction than in the perpendicular direction.

Resume : Boron-doped diamond (BDD) electrodes have attracted considerable attention due to their excellent electrochemical properties, and they have been utilized for the electrochemical applications such as wastewater treatment and electrochemical sensors. On the other hand, BDD electrodes have been prepared mainly by two kinds of chemical vapor deposition (CVD) methods: a microwave plasma-assisted (MP) method and a hot filament (HF) method. However, there are few reports comparing the electrochemical properties of BDD electrodes prepared by these two CVD methods. In this study, we have prepared and investigated several kinds of BDD electrodes with different boron concentration using MPCVD and HFCVD methods to compare the electrochemical properties of them systematically. The electrochemical properties of BDD electrodes were examined by cyclic voltammetry (CV) measurements in an aqueous solution of 1 mM potassium ferricyanide and 1 M KCl. From the CV curves, the anodic and cathodic peak separation increased with decreasing boron concentration. Furthermore, the values of the peak separation were different between BDD prepared by MPCVD (BDD-MP) and BDD prepared by HFCVD (BDD-HF), even though they had almost the same boron concentration. In case of the high boron concentration, the peak separation on BDD-HF was larger than that on BDD-MP. On the other hand, in case of the low boron concentration, the opposite tendency was observed. To reveal the mechanism of these trends, we are currently investigating the electrical and structural properties.

Resume : Photovoltammetric behaviors of different reversible reaction systems including 2.4-chlophenol (DCP), hydroquinone (HQ) and K3[Fe(CN)6] were investigated on a hybrid film prepared with CdS quantum dots and low content of graphene (G). The cyclic voltammetric (CV) curves of HQ and K3[Fe(CN)6] showing a pair of redox peaks became sigmoidal in shape under visible light illumination. In contrast, the CV curve of DCP showing an oxidation peak did not change in shape under the illumination. This result revealed the reversibility-dependent photovoltammetric curve shape, despite of enhanced oxidation currents in all the three reaction systems due to photoelectrocatalysis. Furthermore, we studied the photovoltammetric behaviors of three reaction systems at different pH values, scan rates, intensities of light source and concentrations of reactant. It was observed that that the photovoltammetric curve shape was not changed by pH and intensity of light source, but was tunable with scan rate and concentrations of reactant.

Resume : Micro-electrical mechanical systems incorporate the actuation, perturbation, and sensing of micron level mechanical devices within electronic circuits. They can be used to detect mass1, force2 and displacement. Ultra-sensitive detection of these parameters is important for many bio-medical applications3,4. Apart from ultra-sensitive nature of detection it is important to have the detectors made out of materials which are bio-inactive, making diamond an excellent candidate for such devices due to its bio-compatibility5. While thin film diamond can be grown in both single-crystal and polycrystalline forms, the retention of many of the properties of bulk diamond and possibilities of large area deposition make nano-grained nanocrystalline diamond (NCD) a viable alternative. However, the downside of the NCD is the inherent surface roughness that comes due to its growth mechanism6. Palasantzas7 have shown that surface roughness in a mechanical devices can lead to reduced sensitivity. To get around this problem we have developed a chemical mechanical polishing technique capable of generating smooth diamond surfaces, however the rate of polishing is extremely slow (20nm/h). In this work, we explore the effects of addition of strong oxidizing agents to the polishing fluid on the roughness reduction rate of diamond films. A series of diamond films were grown on silicon dioxide buffered silicon using CVD. The films were polished for four hours and the roughness monitored by atomic force microscopy after each hour of polishing. The base slurry for polishing was colloidal silica based SF1 from Logitech. The slurry could reduce a nominal roughness of ~24nm RMS on as grown diamond films to ~2nm RMS over 25 µm2 within four hours of polishing. The same slurry with trace amounts of Fe(NO3)3 or KMnO4 could polish the films to ~2nm RMS roughness with just 2 hours of polishing clearly indicating an increased polishing rate. Similar enhancement was not seen for slurry with hydrogen peroxide. References 1 K. Jensen, K. Kim, and A. Zettl, Nat. Nanotechnol. 3, 533 (2008). 2 J. Moser, J. Güttinger, a Eichler, M.J. Esplandiu, D.E. Liu, M.I. Dykman, and a Bachtold, Nat. Nanotechnol. 8, 493 (2013). 3 K.J. Rebello, Proc. IEEE 92, 43 (2004). 4 S. Bhansali and A. Vasudev, editors , MEMS for Biomedical Applications (Woodhead Publishing Limited, Sawston, Cambridge, UK, 2012). 5 L. Tang, C. Tsai, W.W. Gerberich, L. Kruckeberg, and D.R. Kania, Biomaterials 16, 483 (1995). 6 O.A. Williams, Diam. Relat. Mater. 20, 621 (2011). 7 G. Palasantzas, Appl. Phys. Lett. 90, 1 (2007).

Resume : Due to their desirable physical and chemical properties, porous 3C-SiC films are a fascinating structure among all potential 3- and low dimensional structures of SiC. In this work, we demonstrate a feasible, controllable, and ?template-free? approach to fabricate porous 3C-SiC thin films, which combines the deposition of diamond/?-SiC composite films with a subsequent high temperature selective oxidation step of the diamond phase. Following this approach, porous 3C-SiC films with different crystallite sizes are obtained. The porosity of these films can be tuned by controlling the amount of the diamond phase in the composite films. The effect of high temperature heating on the SiC films is investigated, which, in turn, allows to identify the optimum temperature for preparing porous 3C-SiC films. SEM, Raman measurements and electrochemical tests are carried out to characterize the films before and after the oxidation process. The porous films fabricated in this way showed strongly increased capacitance compared to pure SiC films rendering them ideal candidates for numerous potential applications in the field of sensors, bio-interfaces and filters.

Resume : Supercapacitors are high power energy storage devices with long cycling lifetimes that are generally safe and reliable. Supercapacitors typically use aqueous electrolytes as charge carriers. An alternative to these are solid state gel electrolytes, which result in supercapacitors that are flexible, less likely to leak and safer to use. Currently, commercial supercapacitors are made from materials that generally are not environmentally friendly. Carbonised biomass is an alternative material that is receiving increasing amounts of interest, as it is renewable, environmentally friendly, and relatively cheap to produce. Seaweed fibre is a natural, abundant cellulose material with uniform dimensions ten times smaller than other plant-based fibre. In this work we converted seaweed fibre into a functionalised carbon material by a thermal carbonisation method, and then developed a novel method to manufacture a high capacitance solid state supercapacitor. A sound performance was obtained by using KOH and poly(vinyl alcohol) (PVA) as an electrolyte. However the supercapacitance deteriorated significantly with increasing charge-discharge cycles. To improve the stability, ionic liquid/PVA electrolytes were used. After 1000 cycles a GCD showed that over 90 % of the original capacitance was retained.

Resume : Ni hydroxides is one of the multitudinous promising electrochemical capacitors materials due to its high capacitance, relatively low-cost, almost pollution-free and good redox activity. On the other hand, graphene has attracted lots of attention also for potential electrochemical capacitors owing to its outstanding electrochemical stability, large specific surface area and high conductivity. In our work, the graphene doped Ni(OH)2 nanoflims are deposited on the Nickel Foam’s porous framework via a simple solvothermal process. The as-prepared graphene doped Ni Hydroxides and nickel foam ternary composite (named GNOH /NF) electrode exhibits a good specific capacitance of 1951.1 F.g-1 at current density of 1 A/g. And the specific capacitance still remains 772.6 F.g-1 (39.6 % compared with its initial 1 A/g) at a very high current density of 40 A/g, the ternary composite electrode also demonstrates excellent flexibility and stable cycle lifetimes (almost no capacitance loss after 500 cycles). Additionally, the asymmetric supercapacitor is successfully assembled by using GNOH /NF as the positive electrode and reduced graphite oxide deposed on nickel foam (rGO /NF) as the negative electrode. The GNOH /NF // rGO /NF device exhibits a relatively high energy density of 22.5 Wh kg -1 at a power density of 4.0 kW kg -1 with excellent cycling performance( 107.6 % capacitance retention over 1000 cycles), and we believe it is a promising candidate for energy storage devices.

Resume : In this paper, we developed an electrochemical sensor for rapid detection of phoxim in marine products based on a zirconium dioxide (ZrO2) nanoparticles decorated hemin functionalized reduced grapheme oxide (hemin-rGO) modified grassy carbon electrode (ZrO2/hemin-rGO/GCE). The surface of modified electrode was characterized by TEM, UV-vis spectroscopy and XPS, and the electrochemical behavior of phoxim at the modified electrode was studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronocoulometry. The ZrO2/hemin-rGO/GCE was applied to the selective amperometric detection of phoxim at a working potential of -0.2 V (vs. Ag/AgCl) in pH 6.0 PBS. Under optimized conditions, the cathodic peak current was proportional to the phoxim concentration over a wide range of 0.03 ? 1.5 ?M, with a detection limit of 1×10^-10 M (S/N = 3). The proposed phoxim electrochemical sensor also exhibited a relative standard deviation (RSD) of 4.8% for a seven-replicate analysis of 5 ?M phoxim, and the response of the electrode declined by 5.0% after 9 days at ambient temperature. The results indicate that amperometric method has the potential in rapid and sensitive detecting phoxim residue in marine products.

Resume : Salmonella is one of the main pathogens which cause human foodborne disease. In this work, an electrochemical biosensor is developed for detection of invA gene of Salmonella based on hairpin assembly target recycling amplification strategy without nuclease and excellent composite of polypyrrole (PPy), reduced graphene oxide (rGO) and gold nanoparticles (AuNPs). A one-step electrochemical approach for fabrication of PPy?rGO?AuNPs nanohybrid composite onto a glassy carbon electrode (PPy?rGO?AuNPs/GCE) is described. PPy?rGO?AuNPs/GCE has a good ability of accelerating electron transfer and provide specific surface area to immobilize thiol-modified hairpin DNA strand 1 (S1) through Au-S affinity. The presence of target invA gene DNA can open hairpin S1 which lead hairpin assembly reaction, therefor the target DNA cycle constantly and biotin label hairpin S2 be fixed increasingly through DNA chain displacement process, so as to combine more HRP to the electrode by affinity interaction of biotin-avidin. Duel strategy amplifies final electrochemical response signal of catalytic reaction of hydrogen peroxide. The developed biosensor provides a composite mode between nanohybrid composite and enzyme-free target recycling strategies thus opens a promising avenue for the detection of ultra-low abundance invA gene of Salmonella in bioanalysis and clinical research.

Resume : Carbon nanostructures with precisely controlled shapes are difficult to be synthesized. In this presentation, we propose a facet-selectivecatalytic process to synthesize polymer-like carbon nanostructures with different shapes. A thermal chemical vapor deposition process was applied to grow these multi-branched carbon nanostructures at temperatures lower than 350 oC. Cu nanoparticles were utilized as the catalyst and acetylene as the reaction gas. The growth of those multi-branched nanostructures was realized through the selective growth of polymer-like sheets on certain indexed facets of Cu catalyst. In this way, straight carbon nanofibers (CNFS), carbon nano Y-junction, carbon nano-hexapus, and carbon nano-octopus were obtained [1]. The vapor–facet–solid (VFS) mechanism, as a new growth mode, has been proposed to interpret such a growth, which contains the steps of formation, diffusion, and coupling of carbon-containing oligomers, as well as their final precipitation to form nanostructures on the selective Cu facets [1,2]. Further synthesis of carbon nanofibers (CNFS)/Co(OH)2 nanocomposites was conducted in ethanol at 50 V for 2 min onto gold electrodes. The formed CNFS/Co(OH)2 matrix was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy and cyclic voltammetry. Its electrocatalytic properties towards the oxidation of glucose in 0.1 M NaOH were tested. A detection limit of 5 mM with the linearity in the range of of 10 mM to 0.12 mM was obtained [3]. [1] Y. Ma, X. Sun, N. Yang, J. Xia, L. Zhang, X. Jiang, Chemistry - A European Journal, 2015, 21(35), 12370 - 12375. [2] Y. Ma, C. Weimer, N. Yang, L. Zhang, T. Staedler, Xin Jiang, Materials Today Communication, 2015, 2, e55-e61. [3] Q. Wang, Y. Ma, X. Jiang, N. Yang, Y. Coffinier, M. Li, R. Boukherroub, S. Szunerits, Electroanalysis, 2016, 28(1), 116-125.

Resume : Carbon electrodes have the advantages of being chemically inert at negative potential ranges in all media and high offset potentials for hydrogen evolution in comparison to metal electrodes, and therefore are the most suitable electrodes for electrochemistry and electrochemical conversion of CO2 into valuable chemicals [1]. In this presentation, we summarize on carbon electrodes the voltammetry, electrochemical and electrocatalytic CO2 reduction, as well as electron synthesis using CO2 and carbon electrodes. The photoelectrochemical CO2 conversion using a CO2 adsorption-enhanced semiconductor/metal-complex hybrid photoelectrocatalytic interface will be highlighted. In such an interface, a carbon aerogel is employed as the CO2 fixation substrate, Co3O4 as the light harvester, and Ru(bpy)2dppz as the electron transfer mediator and CO2 activator. The CO2 surface concentration exhibits a 380-fold increase on this hybrid interface than that on Co3O4/FTO. The CO2 conversion to formate occurs at an onset potential of -0.45 V (vs. normal hydrogen electrode, NHE) under photoelectrochemical conditions, 160 mV more positive than its thermodynamic redox potential. At an applied potential of -0.60 V (vs. NHE), the selectivity of the formate yield reaches 99.95%, with a production rate of approximately 110 μmol cm-2 h-1, a faradaic efficiency of 86%, and and an electron transfer rate of 2.94×10-3 cm s-1. An instantaneous proton-coupled electron transfer process is confirmed during such a conversion. This originates from the rapid photoelectrochemical activation of bpy and dppz in Ru(bpy)2dppz as well as the synergic effect from the promoted CO2 adsorption and the applied molecular catalysis [2]. [1] N. Yang, S. R. Waldvogel, X. Jiang, ACS Applied Materials and Interface, 2016, 8(42), 8357-28371. [2] X. H. Q. Shen, J. Liu, N. Yang, G. Zhao, Energy Environ. Sci., 2016, 9, 3161-3171.

Resume : In most of graphene based electrochemical applications, graphene nano platelets (GNPs) have been applied. In our studies, we investigate first electrochemical properties of GNP regarding its electrochemical activity, potential window, and double-layer capacitance. These properties are compared with those of carbon nanotubes (CNTs) [1]. The GNP is then functionalized with metal nanoparticles [2,3], and small linker molecules [4], and big molecules [5,6]. These interfaces were characterized using various techniques such as SEM, AFM, XPS, and electrochemical techniques. They were further applied for sensing endocrine disrupting chemicals [1,3,6] and small-sized ions [4], oxidation of hydrazine [2], and for biosening [5] . The results confirm that GNP is thus more promising than CNT for electrochemical applications, e.g. for electrochemical detection and removal of endocrine disrupting chemicals. [1] Q. Wan, H. Cai, Y. Liu, H. Song, H. Liao, S. Liu, N. Yang, Chemistry – A European Journal, 2013, 19(10), 3483-3489. [2] Q. Wan, Y. Liu, Z. Wang, W. Wei, B. Li, J. Zou, N. Yang, Electrochemistry Communication, 2013, 29, 29-32. [3] D. Su, Y. Zhang, Z. Wang, Q. Wan, N. Yang, Carbon, 2017, 117, 313-321. [4] Z. Qiu, J. Yu, Y. Peng, Z. Wang, Q. Wan, N. Yang, ACS Applied Materials and Interface, 2016, 8(42), 28291-28298. [5] X. Luo, Z. Qiu, Q. Wan, H. Shu, N. Yang, Phys. Status Solidi A, 2014, 211(12), 2795-2800. [6] B. Li, Z. Qiu, Q. Wan, Y. Liu, N. Yang, Phys. Status Solidi A, 2014, 211(12), 2773-2777.

Resume : Gold nanoparticles (Au NPs) and graphene doped CdS (GR-CdS) were employed to fabricate a PEC aptasensor for diclofenac (DCF). It was observed that GR-CdS modified electrode exhibited a high and stable photocurrent upon visible light illumination, due to the excellent electrical and optical property of GR as well as the high absorption efficiency of CdS in the visible region. While Au NPs were added to GR-CdS/FTO, a further enhancement in photocurrent response was observed owing to surface plasmon resonance. Moreover, the Au NPs were advantageous to immobilize the SH-terminated aptamer used as a biorecognition element to DCF. Upon interaction of DCF with the immobilized aptamer, the DCF molecules were captured by the aptasensor. When the sensor was illuminated with visible light, an enhanced PEC current response was observed due to the oxidation of the captured DCF by the photogenerated holes. Under the optimized conditions, the sensor showed a PEC response to DCF in the linear range of 1 to 150 nM, with a detection limit of 0.78 nM. Thus, a highly selective and sensitive PEC sensor for the determination of DCF was provided.

Resume : Electrochemical sensors based on hemin-graphene nanocomposites (H-GNs) and molecularly imprinted polymer are developed for sensitive and selective detection of 4-aminophenol (4-AMP). The 4-AMP molecularly imprinted polymer was prepared successfully by using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethaerylate (EGDMA) as crosslinker. The MIP was characterized by infrared spectroscopy and scanning electron microscopy. H-GNs were synthesized through the π-π interactions. H-GNs, serving as the loading platform for MIP immobilization, have intrinsic peroxidase-like activity, which can catalyze the reaction of 4-AMP. As an electrochemical sensor, the MIP/H-GNs/GCE exhibited strong catalytic activity toward the reduction of 4-AMP which was demonstrated by cyclic voltammetry (CV). Under optimized conditions, the sensor showed a linear response to the concentration of 4-AMP in a range from 0.3 to 25 μmol•L−1 （R2=0.997）with a detection limit (3S/N) of 0.06 μmol•L−1. Moreover, the imprinted sensor exhibited excellent specific recognition ability to 4-AMP which could avoid the interference of other structurally similar phenolic compounds. The proposed electrochemical method was successfully applied to produce a sensor for the detection of 4-AMP in real water samples.

Resume : An interface was fabricated using carbon nanotubes (CNTs) as the catalyst support and palladium nanoparticles (Pd) as the electrocatalysts. The Pd/CNT nanocomposite was synthesized with ethylene glycol reduction method. Such a nanocomposite based interface was characterized using transmission electron microscope, energy dispersive X-ray spectroscopy, x-ray diffraction, voltammetry, and impedance. On the Pd/CNT coated electrode, the electrocatalytic oxidations of those liquid fuels (e.g., alcohols, carboxylic acids and aldehydes) occur similarly in two steps: the oxidations of freshly chemisorbed species in the forward (positive-potential) scan, and then in the reverse scan (negative-potential) the oxidations of the incompletely oxidized carbonaceous species formed during the forward scan. The oxidation charges are adopted for the first time to study their oxidation mechanisms and oxidation efficiencies. The oxidation efficiency follows the order of aldehyde (formaldehyde) > carboxylic acid (formic acid) > alcohols (ethanol > methanol > glycol > propanol). Such a Pd/CNT coated electrode is thus promising to be applied as the anode for the facilitation of direct fuel cells.

Resume : A bucky-gel based electrode, composed of dithizone, ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate), and multi-walled carbon nanotubes (MWCNTs), was fabricated. After its optimization, this electrode was characterized using scanning electron microscope, voltammetry, electrochemical impedance spectroscopy, and chronoamperometry. On a bucky-gel coated glassy carbon electrode, femtomolar (fM) leveled lead ions were electrochemically detected using differential pulse anodic stripping voltammetry. After the accumulation of lead ions into the bucky-gel modified electrode at −1.2 V vs. saturated calomel electrode for 5 min in a pH 4.4 sodium acetate–acetate acid buffer solution, an anodic wave at −0.58 V is noticed. The anodic peak current is detectable for lead ions in the concentration range from 1.0 μM down to 500 fM. The detection limit is calculated to be 100 fM. The proposed method was successfully applied for the detection of lead ions in lake water.

Resume : Nowadays, graphene/reduced graphene oxide has attracted more concerns because of its superior mechanical strength, low density and high heat conductance. The various applications have been developed on its mechanical, electrical and chemical properties. The property of graphene with larger surface area and better conductivity makes molecular imprinting electro-polymerization monomer to produce polymeric membrane with more effective imprinted sites, greater adsorption capacity and adsorption efficiency. Graphene and its composites is suitable for modifying electrochemical biosensors. In the last few decades, various papers have been reported about chemical, optical, adsorption and electronic properties of nanostructured materials. Especially AuNPs are used frequently as electrode surface in the fabrication of sensors/biosensors. In addition, the nano-sized AuNPs can enhance the electrode conductivity, the rate of electron transfer and the analytical sensitivity. Therefore, nano-sized AuNPs and its composites is suitable for building electrochemical biosensors. Erythrosine(ERT,C20H6I4Na2O5), as a synthetic pigment, often used in fruit flavor drinks, cakes, candy, dispensing wine, carbonated drinks and other foods. Because of their bright colors, good dyeing force, the price is cheap, widely used in food processing. But studies have shown that almost all of the synthetic pigments cannot provide nutrients to the human body, some synthetic pigment even endanger human body health for its carcinogenicity. Erythrosine belongs to a synthetic pigment and is a kind of widely used in food industry of colorants, due to the dangers of excessive edible has the potential to human body health, the daily intake of erythrosine are restricted. In view of the widespread existence of ERT and its harmfulness, to establish an efficient, fast, accurate, simple and economical method to detect ERT is very necessary. Molecularly imprinted polymers shows selective recognition of specific molecules caused by the covalent or non covalent interactions between the template molecules and functional monomers. It possesses the ability to selectively identify target molecules, and have the advantages of anti-acid and alkali resistance, good atability, easy preparation and so on. In this paper, a high sensitivity and quantitative detection of ERT molecularly imprinted membrane sensor was successfully constructed based on the electro-polymerization technology and a sensitive imprinted electrochemical sensor based on gold nanoparticles(AuNPs) in 2-aminoethanethiol(2-AET) functionalized graphene oxide(GO) modified glassy carbon(GC) electrode was fabricated for fast and direct determination of erythrosine.

Resume : The ocean oil spills are one of the largest environmental threats caused by human activity. Therefore, it is the matter of highest importance to find efficient ways of removing oil from ocean's water table. The recent progress in nanotechnology showed that properly engineered carbon nanomaterials are superhydrophobic and may act as selective oil sorbents [1,2]?. Moreover, their low cost makes using them feasible in industrial applications. In this research we propose coating cellulosic materials by graphene flakes by simple dip coating method. The obtained cellulose/graphene filter is highly hydrophobic and simultaneously strongly absorbs oils and organic solvents. Additionally, it was proofed that the procedure is applicable for various cellulosic materials, showing different purity and porosity. It was shown that absorption selectivity exceeds 90% for each cellulosic material and reaches 99% for the best samples. Moreover, different carbon nanomaterials, such as carbon nanotubes and carbon black, also gave promising results. References [1] Gupta, S.; Tai, N.-H. J. Mater. Chem. A 2016, 4 (5), 1550?1565. [2] Ge, B.; Zhang, Z.; Zhu, X.; Men, X.; Zhou, X.; Xue, Q. Compos. Sci. Technol. 2014, 102, 100?105.

Resume : We investigate the influence of annealing to Metal/Graphene contacts. CVD grown graphene is transferred on already patterned CTLM metal (Nickel and Gold) contacts. ‘’Top transfer’’ strategy directly allows to investigate the topography of graphene surface and to measure electrical properties of graphene layer induced by metal contacts. Raman spectroscopy, Kelvin Probe Force Microscopy (KPFM) and optical sample observation were used to associate surface morphology to surface electrical properties and modifications induced by thermal anneal. The stress and doping effects of graphene layer could be interpreted referring to Raman and KPFM spectroscopies. Defects or contamination observed in optical images of sample could be easily identified at Raman spectroscopy mapping and KPFM images. We conclude that two main mechanisms of Metal/Graphene contacts occur during anneal process. These both mechanisms improve electrical interaction of Metal/Graphene structure. The first mechanism is effected by physical or chemical adsorption of graphene layer to metal contacts. This process most dominant within a few minutes of anneal time. By increasing anneal time we observe the second process – graphene layer doping by metal contacts. Strain effects occur at graphene layer in contact to metal surface. Furthermore, combination of KPFM mapping and Raman spectroscopy mapping gives essential information about graphene transferred on the top of contacts.

Resume : In this work, we will address the utilisation of novel micro/nano structures created by top-down approaches on the surface of highly conductive boron-doped diamond films for the enhancement of electrochemical detection in aqueous media. Boron-doped diamond (BDD) films have been used since many years as electrodes in environments that require high electrode stability, robustness and reproducibility. More recently, diamond has been applied as (micro)electrodes for (bio)electrochemical sensing, due to its large potential window, low background current and inherent biocompatibility. Typically, as-grown BDD films are used for such purposes. A few reports on nanostructured BDD films have already demonstrated substantial performance gains in electrochemical sensing. However, structuring all-diamond electrode surfaces involves complex cleanroom processing (e.g. lithography, reactive ion etching) that are costly and time-consuming, and therefore new fabrication routes are desirable. Here, we will describe novel, simple and straightforward fabrication techniques for diamond surface structuring. The electrochemical sensing performance of the fabricated BDD electrodes will be evaluated with standard, typically employed redox couples, and contrasted with as-grown electrodes. Finally, novel application towards glucose sensing will be explored. The electrochemical characterisation will be done by cyclic voltammetry and electrochemical impedance spectroscopy.

Resume : Hybrid systems combined diamond NEMS cantilevers with electrochemical techniques provide a promising scheme for high-resolution electrochemical sensors with wide potential window and excellent chemical inertness. The authors report on the marked improvement of the quality factor (Q-factor) of single crystal diamond (SCD) nanoelectromechanical system (NEMS) resonators through annealing in oxygen ambient. The SCD NEMS resonators were fabricated by ion implantation assisted technique. The resonance frequency followed well the inverse power law relationship with the length of the cantilevers despite of the annealing. It was observed that there was little modification in the resonance frequency and Q-factor at 430 oC, while an obvious red-shift in the resonance frequency occurred at 500 oC. Meanwhile, a marked improvement in the Q-factor from around　3500 to 7000 was observed at 500 oC. The frequency red shift is due to the etching of diamond with a rate of 0.4-0.5 nm/hour at 500 oC. The analysis of the energy dissipation discloses that the surface effect dominates the energy loss mechanism for the SCD NEMS resonator. The improvement of the Q-factor is thus attributed to the elimination of the surface defects. The SCD NEMS resonators provide a sensitive scheme to function as electrochemical sensors or to examine the interface interactions between reactants during the electrochemical process.

Resume : Tremendous research efforts have been dedicated to fabricating high quality Zn-doped CdTe quantum dots for any potential biomedical applications. In particular, the correlation of issues regarding how QDs interact with DNA is of greatest importance. Herein, a pH-responsive study of the interactions between CdTe:Zn2+ quantum dots with four different sizes and calf thymus DNA (ctDNA) was conducted using multispectroscopic techniques and electrochemical investigation. Fluorescence studies revealed that this interaction process is predominantly a static processs and groove binding was the main binding mode for CdTe:Zn2+ QDs to DNA, the thermodynamic parameters ΔG, ΔH, and ΔS with temperatures changes indicated that the hydrogen bonds and van der Waals interactions played major roles in the reaction. Furthermore, CD spectroscopy analysis indicates that the normal conformation of DNA is discombobulated by CdTe:Zn2+ QDs. In addition, the electrochemical behaviour of the affinity of CdTe:Zn2+ QDs for DNA agreed well with the results obtained from fluorescence experiments. This study might be meaningful for understanding of the molecular binding mechanism of QDs for DNA and provides a basis for QDs labeled systems.

Resume : Carbon dots (CDs) are a star of carbon nanomaterials because of their superiority in water solubility, chemical inerness, low toxicity, ease of functionalization and resistance to photobleaching. Carbon dots have been widely applied in bioimaging and nanomedicine. In this study, bovine serum albumin (BSA) was chosen as a template protein to explore the interaction between serum proteins and CDs. Our group selected a bottom-up synthetic route, One-pot green synthesis CDs by used ascorbic acid as carbon precursor water phase reflow at 90℃ under strirring for 2.5h, and the CDs of we synthesis emit colour is different between that many people used ascorbic acid as carbon precursor. UVvis absorbance, fluorescence spectroscopy, and electrochemical approaches ect will be choose to explore interaction between the CDs and BSA.

Resume : Currently, renewable and low-cost electrode materials are being intensively pursued to meet the development of sustainable electrochemical energy-storage systems. Chitin, which is the second most abundant biopolymer throughout the natural world derived from the exoskeletons of arthropods and shells of cephalopods, owns many attractive properties such as renewability, nontoxicity, intrinsically fibrous structure and high content of nitrogen. Herein, the nitrogen-doped amorphous carbon nanofibers (NACF) fabricated by directly pyrolysis of chitin is used as anode material in potassium ion batteries (KIBs) for the first time. The NACF electrode delivers excellent performance, such as high capacity, high rate capability, and stable long cycling life. The superior electrochemical performances are mainly attributed to synergistic effect of the unique one-dimensional porous nanofibers benefiting the transmission of electron/electrolyte, and the N-doped amorphous nanostructure increasing electrical conductivity and active sites. Our work provide a new approach for the preparation of heteroatom-doped carbonaceous materials with unique porous nanofibers microstructure using natural enlightenment, which should inspire us to explore more other advanced materials with value-added attributes by treatment of renewable bio-waste.

Resume : Enormous research efforts have been contribute to the design and fabrication of exceptional structure with higher complexity, hoping to develop supercapacitors in order to meet the growing demands for both high power density and energy density. Herein, we have designed and fabricated a hierarchical structure of a Co3O4@ biomass-derived carbon fiber @Co3O4 (@BCF@) consisting of hollow porous carbon fiber as the sandwich layer and Co3O4 particles both as an internal shell and an external cladding layer. When @BCF@ are used for supercapacitors, possesses excellent electrochemical performances, such as high specific capacitances (892 F g?1 at a current density of 0.5 A g?1) and long-term cycling stability (retained 88% even after 6000 cycles). Meanwhile, it also exhibits the potential application value in asymmetric supercapacitors. The selected biomass-sandwich carbon fiber with porous structure not only can provide ideal ?electron superhighway? to surmount the blemish of the high resistance in great majority of the oxide electrodes, but also serve as the available backbone of inner wall space, which could load more Co3O4 particles per unit electrode area to maximize redox reaction. This eximious biomass-sandwich structure provides an electrode candidate that is promising for the development of energy storage devices in the near future.

Resume : Innovative energy storage technology lies at the heart of the advances that have already been made in energy conversion and storage devices, for example the introduction of supercapacitors. They can operate at high charge and discharge rates over an almost unlimited number of cycles and realize energy recovery, and therefore are gaining increasing popularity in high power energy storage applications. Specifically research and industrial developments for supercapacitors are essentially oriented to improving the device?s energy density through the design of novel electrode concepts. Herein, nickel foam as an ideal electrode architecture, which consists of a 3D interconnected network of electronic transmission. More interesting, uniform nano carbon particles (~20 nm) will be generated and can be well distributed on the surface of nickel substrate in a candle flame. The synthesized carbon particles consisted of a unique structure of 3D chain-like interconnected struts with highly wrinkled surfaces. Unlike other fabrication methods of supercapacitor electrodes, the processing described in this work is fast and straightforward, with no toxicity. Electrochemical measurements indicated that the flame-spray processing of supercapacitors obtained a high electric double layer capacitance (236.8 F g-1 at 0.3 A g-1) and excellent cycling stability (only 3% loss was observed after 10000 cycles at 5 A g-1), which are much higher than the electrodes fabricated by a traditional binder-bearing technique.

Resume : Fullerene can be potentially used as the electrocatalyst for oxygen reduction reaction (ORR) due to its curvature and pentagon defect. In this study, the ORR mechanisms and catalytic abilities of pure and N-doped fullerenes were investigated via DFT computations. Four different sized fullerenes, C20, C40, C60, and C180, with respectively the diameter of approximately 0.4, 0.6, 0.7, and 1.2 nm, were utilized to investigate the size effect on the ORR performance. The results reveal that the smallest (C20 and N-doped one) and the largest (C180 and C179N) fullerenes are not effective ORR catalysts candidates due to their unsuitable adsorption strength to the ORR species. In contrast, N-doped C40 and C60, with the adsorption energy much close to those on Pt(111), manifest high ORR activity potentials. Further analysis of the relative energy diagram shows that the ORR process on C19N and C179N is completed through a H2OO dissociation mechanism, while on C39N and C59N it will undergo an OOH dissociation pathway. In addition, the C39N has the largest decreased energy of rate-determining step in the relative energy profile, suggesting its ORR activity is the best among all the different sizes of fullerenes we studied.

Resume : 1-[3-(N-Pyrrolyl) propyl]-3-butylimidazolium bromide ionic liquid was synthesized, and was used as a modifier to functionalize graphene oxide nano-sheets through the interaction between the carboxyl anion and imidazolium cation to produce a graphene oxide-ionic liquid nanocomposite. The obtained graphene oxide-ionic liquid nanocomposite was drop coated onto a glassy carbon electrode surface, and then cyclic votammetric scanning was performed to polymerize ionic liquid to fabricate a graphene oxide/poly ionic liquid nanocomposite film modified electrode. X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy and electrochemical impedance spectroscopy were used to characterize the obtained graphene oxide-ionic liquid nanosheets and the nanocomposite film modified electrode. Electrochemical behavior of bisphenol A at the film modified electrode was investigated, and the experimental conditions for the determination of bisphenol A were optimized. An irreversible oxidation peak was observed for bisphenol A at the nanocomposite film modified electrode. Compared with bare glassy carbon electrode, the oxidation peak current of bisphenol A at the nanocomposite film modified electrode was significantly increased. A good linear relationship between the oxidation peak current and the bisphenol A concentration was found in the range of 2.0 × 10-7 ~ 1.0 × 10-5 mol L-1, the detection limit was 1.7 × 10-8 mol L-1. The method was successfully used for the determination of bisphenol A in plastic drinking bottle, and the results were consist with these obtained by high performance liquid chromatography.

Resume : It is of great significance to develop efficient monitoring strategies with high sensitivity and selectivity for MC-LR, one of the most highly concerned typical microcystic toxins in water samples. A convenient signal-on electrochemical aptasensor for E2 was proposed based on graphene controlled assembly and DNase I enzyme cleavage-assisted target recycling amplification strategy, as well as Au nanoparticles’ synergistic effect. Highly sensitive detection of MC-LR was achieved with a linear range from 1.0 to 100.0 pM and the detection limit of 0.8 pM, attributed to the double signal recycling amplification functions. Besides, this method also exhibited high selectivity while being used to detect 100-fold concentration other six potential coexisting interferents containing N and P, such as omethoate, glyphosate, paraquat, trichlorfon, acetamiprid and monosultap. Real water sample analysis showed its reliability and potential in practical environmental monitor. A promising electrochemical aptasensor platform towards MC-LR with high selectivity and sensitivity has thus been provided. (Acknowledgements: National Natural Science Foundations of China (NSFC) (No. 21377092), and the Fundamental Research Funds for the Central Universities.)

Resume : The worldwide use of atrazine, a kind of the most widely used triazine herbicides, had caused a great influence on the environmental and human health because of its potential disrupter of cell chromosome structure, estrogens metabolism and immune systems. Traditional detection methods of atrazine usually suffer from limitations of slow speed, complex analysis process, high cost, and not applicable for field monitoring, etc. It is of great significance to develop a convenient and on-site capable detection method towards atrazine. Self-powered sensors had attracted great attention in the past decade due to their capacity of harvesting energy from the environment and had no requirement for external electrical power supply during the chemical sensing of analytes. It is particularly outstanding in great potential for its feasible in on-site monitoring, which is highly demanded for the environmental monitoring issues. So far, most of the sensor were based on biofuel cell (BFC) or microbial fuel cell (MFC), which had been applied in medicine and biological analysis. While the self-powered sensors have seldom been applied in environmental analysis because of the much severe and complexed condition of the samples, which might be advertised to the performance of the BFC or MFC, as well as the potential demands in high acidic or basic environment. At the same time, low output signal, insufficient stability in a complex environment due to the enzyme deactivation, and poor in selectivity towards special targets of most of the self-powered sensors are the also their main obstacles. In the present work, we developed a self-powered aptasensor system to detect environmental pollutant atrazine with high selectivity based on a kind of very simple glucose biofuel cell as anode and an aptamer-loading electrode as cathode. By virtue of using carboxylated multi-walled carbon nanotubes (MWCNTs) as the functional bridge for the anode substrate electrode and the biomolecule glucose dehydrogenase, stable and strong output power density signal can be obtained with nicotinamide adenine dinucleotide (NAD +/NADH) used as a cofactor. The carboxylated multi-walled carbon nanotubes (COOH-CNTs) not only played a key role in linking bio- enzyme molecule to substrate electrode, but also improved the effciency of electron transfer due to its good conductivity. Meanwhile, anti-atrazine aptamer was loaded to gold electrode to serve as the recognition elements to atrazine. When atrazine was combined with aptamer specifically, the formation of its steric hindrance and electrostatic repulsion can blocked the electron transfer efficiency in cathode surface, thus resulted a remarkable decrease of biofuel cell in output power density. Based on this principle, the constructed sensor has been successfully proposed to detect atrazine with high selectivity. A detection limit of 10 nM was reached. A simple, fast, efficient, low-cost, and especially self-powered sensing platform to atrazine has been provided, with no need of an external power supply. It opens promising prospects of self-powered aptasensor to the practical application in the environmental water pollution treatment and monitoring.

Resume : Microcystin-LR is a widespread and toxic contaminant produced by the freshwater Cyanobacteria. It is an electrochemical inert species which is difficult to be directly detected by a simple electrochemical method. In this study, a highly sensitive and selective photoelectrochemical (PEC) sensor which utilize a graphene-based vertically aligned TiO2 nanotubes (TiO2 NTs) as photoelectrochemical functional interface, and surface molecularly imprinted polymer (MIP) modification as recognition element. The constructed PEC sensor exhibits outstanding performance in MC-LR detection with a linear range from 0.01 to 50 nmol L-1 and a limit of detection of 0.01 nmol L-1.The PEC sensor also presents excellent selectivity while coexist other organic contaminants including monosultap, glyphosate, acetamiprid, omethoate, gramoxone and dipterex with a 100 times concentration than MC-LR. The relative photocurrent of them are all less than 15%. The favorable detection sensitivity is mainly attributed to great conductivity and the giant π-π conjugated structure of graphene, which is great helpful to improve the separation of electron-holes on TiO2 NTs, yielding its enhanced photoelectric activity. The good selectivity of the PEC sensor is resulted from the specific action from the surface MIP layer. A simple and promising PEC sensor towards MC-LR detection has therefore been provided with the potential application capacity in real water samples.

Resume : Effective control of interfacial properties of carbon electrode materials is often critical to achieve their desired performance in applications ranging from electrocatalysis to capacitive storage. Modification of morphology and chemical composition offer versatile routes for tailoring the electrochemical response of these materials. Nitrogen incorporation is of particular interest, as it has been shown to result in increased activity in the oxygen reduction reaction (ORR), a critical reaction in fuel-cell technologies. However, the origin of this activity is not well understood and rational optimization of ORR activity remains challenging due to the interplay among electronic, surface and morphology changes associated to the introduction of N-sites. We report on synthetic strategies for investigating the effect of morphological and chemical changes in carbon materials. First, chemical vapour deposition was used to create graphene-like nanostructured carbon with tailored edge and defect density. A combination of microscopy, spectroscopy and electrochemical methods was used to correlate carbon chemistry and morphology to ORR activity. Second, the effect of nitrogenation was investigated using smooth carbon film electrodes prepared via sputter deposition. A combination of optical and electrochemical methods reveals that low-levels of nitrogenation result in fast electron transfer kinetics compared to non-nitrogenated carbons. Surface effects however can also play an important role in the case of selected redox species due to their interactions with N-sites. Finally, we discuss results on thin film electrodes with homogeneous N-site chemistry as model materials to test the role of N-site chemistry in ORR.

Resume : The structure design of an electrode is one of the most important factors affecting its reaction kinetics, the capability of mass transportation with electrolyte, and consequently the performance of an electrochemical energy storage or conversion system. A successful approach that has been widely demonstrated is to construct a three-dimensional (3D) nanoscale-structured electrode, which enables enhanced ion and electron transport, increased active material loading, and improved mechanical stability. Ascribing to their combined superior inherent properties and the special structure configuration, 3D graphene and transition metal dichalcogenide (TMD) nanostructures have demonstrated promising applications in electrochemical energy conversion and storage. In this presentation, we report our recent progress in applying 3D graphene, TMD and related composites in the electrochemical electrode applications derived from their distinct merits of structure and properties, e.g., supercapacitor, lithium ion battery, vanadium redox flow battery, and fuel cell.

Resume : Development of high temperature polymer electrolyte membrane fuel cells (HT-PEMFC) on polybenzimidazole membrane is highly important for alternative energy because it allows to use hydrogen contaminated with CO. Advances in hydrogen-air HT-PEMFC are related with the increase in durability of membrane-electrode assembly. In order to improve the traditional scheme of electrode producing, carbon black support for the electrocatalyst (Pt, Ni, etc) may be changed by more stable carbon nanostructures. For the first time, we have shown that carbon nanofiber paper, which was obtained by the electrospinning of polymer (such as polyacrylonitrile or polyheteroarylenes) solution with further pyrolysis of self-supporting mats, is suitable for Pt deposition and gas-diffusion electrode producing for HT-PEMFC. Also, we have prepared a composite nanofiber electrode when Zr and Ni salts are added to the polymer electrospinning solution. After pyrolysis (900-1200 oC), Ni(0) and ZrOx particles are incorpotated into carbon nanofibers. As shown, it facilitates Pt deposition which proceeds on Ni(0) nanoparticles. For the new carbon composite electrode, polarization curve characteristics are improved compared to non-composite ones. Polarization curve values reached 0.702 V at 0.2 ?/cm2 and 0.570 V at 0.6 ?/cm2 at 180 oC which is comparable with Celtec® P1000. New carbon materials were characterized by SEM, TEM, EIS, CV, Raman spectroscopy, XPS, standard contact porosimetry, elemental analysis.

Resume : Design of carbon electrodes with large ion accessible surface area and low ion transport resistance is required to achieve high energy- and power-density supercapacitors. Graphene is an attractive material for the supercapacitor electrode due to its large surface area and high electrical conductivity. However, most of graphene electrodes have highly ordered structure where graphene sheets parallel arranged to electrode film, which prevented the ion transport during charge-discharge process. Recently, it is reported that the prevention of restacking in chemically-reduced graphene sheets enable forming the narrow gap between graphene sheets suitable for ion transport [1]. Herein, we try to from disorderly-assembled graphene nanoribbon (GNR) electrode to achieve low ion transport resistance by using pseudo one-dimensional (1-D) GNR instead of 2-D graphene, because 1-D nanocarbon is easy to form the network structure. In the present study, graphene oxide nanoribbon were reduction by hydrazine treatment and GNR films were prepared by filtration directly from the reduced GNR dispersions. During the filtration, the reduced GNRs assembled into a film structure. Our X-ray diffraction analyses demonstrate that the restacking between the reduced GNRs does not occur in the obtained GNR films, indicating that the GNR films has disorderly assembled structure. The GNR-film-based supercapacitor shows high capacitance of 225 F/g at a current density of 0.1 A/g, with superior retention of 71 % even at a high current density of 100 A/g. Disorderly-assembled GNR electrode offers new possibilities of high energy- and power- density supercapacitor with low ion transport resistance. [1] Yang, X. et al. Adv. Mater. 23, 2833 (2011).

Resume : Reduced graphene oxide (RGO) own outstanding physicochemical properties arising from itself structure, having vast active defect sites and functional groups on RGO sheet, exhibiting great potential for practical application. Nevertheless, the aforementioned structure increased the resistance and the effects of van der Waals force during the reduction process. Consequently, in this work, through rapidly, low-cost and reliable candle soot-derived carbon nanoparticles (CNPs) method, using uniform microscale CNPs (~20 nm) serving as template embed into the layers of RGO to construct 3D RGO. CNPs possess a large surface area to promote molecular adsorption at the interface, which could ensure high efficiency during the electrochemical process. This construction resolved the issues of impedance and π-π stacking, moreover, presented remarkable electrochemical performance. Electrochemical capacitive performance of 3D RGO enhanced to 312 F g-1 at a current density of 0.5 A g-1, also demonstrated a long-term cyclic stability (maintained 94.2% capacity even after 10000 cycles). In addition, as a symmetric electrode, 3D RGO has excellent structural advantage, when the operating voltage increased to 1.6V, a further high-level energy density of over 42.3 Wh kg -1 at a large power density of 1280 W kg -1 can be obtained.

Resume : Voltammetric behaviour of the genotoxic pollutant 2-amino-9-fluorenone was investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square wave voltammetry (SWV), in both anodic and cathodic potential regions. Previous work with 2-AFN using a variety of electrode materials had been affected by the extensive fouling, and only periodic mechanical regeneration of the electrode surface achieved repeatability. Boron-doped diamond (BDD) has higher resistance to fouling by analyte media than other electrode materials, we found that 20 pulses of alternating +/10 mA cm2 with 100 ms duration successfully regenerated the BDD surface and produced repeatable currents. The interaction between 2-AFN and guanosine and adenosine, single-stranded DNA, and double stranded DNA were examined at the bare BDD electrode. Additionally, performance of oxygen-terminated BDD decorated with DNA were investigated after exposure to various concentrations of 2-AFN, to characterise the extent of the genetic damage.

Resume : Trace and toxic elements, such as cadmium (Cd2 ) and lead (Pb2 ) pose acute or chronic risks to ecosystem because of their high stability and propagated accumulation through food chains and even threat to human life. Accordingly, exploring the sensitive, rapid and simple analytical method for precise monitoring of Cd2 and Pb2 is urgently needed. Electrochemical anodic stripping voltammetry (ASV) has been widely recognized as a promising method for determination of heavy metals owing to its low cost, good portability and specificity, on-site monitoring, high sensitivity and low limit of detection. A green method is reported to effectively and rapidly reduce graphene oxide to graphene with zinc powder at ambient. ZRGO (zinc-induced in-situ reduction of graphene oxide) was prepared by mixing graphene oxide (GO), zinc (Zn) powder, ammonium chloride (NH4Cl) in solution under stirring conditions at room temperature for 10 min. The as-prepared ZRGO was used to modify the surface of glassy carbon electrode (GCE). During this process, NH4Cl catalyzes the reduction of GO by Zn powder and causes the rapid in-situ reduction of graphene oxide obtained the freshly reduced and nanoporous graphene oxide (that is, ZRGO). The ZRGO nanomaterial were characterized by field emission scanning electronic microscope (FESEM), transmission electron microscope (TEM), atomic force microscopic (AFM), Raman, fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) to prove ZRGO has been successfully prepared. Electrochemical responses of K3[Fe(CN)6] revealed that ZRGO was capable of facilitating electron transfer and increasing surface area. The interface based on ZRGO nanomaterial exhibits a porous and three-dimensional structure, resulting in a high surface area as well as many reactive or adsorption sites for Cd2 and Pb2 . Electrochemical behaviors of Cd2 and Pb2 in water matrix were studied and the anodic stripping peak was completely separated in pH 5.0 acetate buffer solution. Compared with GCE, the ZRGO-modified GCE (ZRGO/GCE) greatly increased the anodic stripping peak currents of Cd2 and Pb2 , showing great signal enhancement effect. More importantly, the response signals of Cd2 and Pb2 on ZRGO/GCE further enhanced remarkably in the presence of Bi3 . The influences of pH value, Bi3 concentration, amount of ZRGO, accumulation potential and time on the anodic stripping peak currents of Cd2 and Pb2 were studied. Based on this sensitization effect, a novel electrochemical sensing platform with high sensitivity, fast and simultaneous detection of Cd2 and Pb2 can be constructed.

Resume : Phenolic compounds are used in various industrial processes, including the preparation of petrochemicals, cosmetics and pharmaceutical products. Phenols are non-biodegradable and toxic to many organisms, and their release into the environment from the waste streams of industrial processes leads to soil and water contamination. Consequently, it is of critical importance to be able to determine levels of phenolic compounds in environmental samples. Electrochemical detection is often used for this purpose; however, the anodic detection of these compounds is complicated by electrode fouling due to electropolymerisation of phenoxy radicals. Carbon nanotubes immobilised onto glassy carbon electrodes have been reported to improve electrode performance for phenol detection; other carbon nanomaterials may therefore be expected to exhibit similar behaviour. In this study, carbon black was chosen as a cheap, readily available carbon nanomaterial to construct high surface area electrodes for use in electrochemical detection of catechol, p-nitrophenol and p-cresol. Modifying a glassy carbon electrode with carbon black is shown to improve the detection sensitivity of all three phenols as evidenced by up to 10-fold increase in oxidation current and up to 150 mV shift to lower overpotential. The reusability of a carbon black electrode in the detection of different phenolic compounds is discussed.

Resume : Graphene was prepared via one-step ultrasonic exfoliation of graphite powder using N-methyl-2-pyrrolidone (NMP) as the solvent with the presence of sodium citrate. The morphology and layer structure were confirmed using SEM and TEM. Electrochemical responses of K3[Fe(CN)6] revealed that prepared graphene was capable of facilitating electron transfer and increasing surface area. On this basis, the prepared graphene was used to modify glass carbon electrode(GCE), then the electrochemical behavior of carbendazim?a kind of pesticide, was studied, and a sensitive oxidation peak was observed in pH 5.7 phosphate buffer. Compared with bare GCE, the oxidation peak current of carbendazim on graphene modified GCE is improved greatly. The influences of pH value, amount of graphene, accumulation potential and time on the oxidation peak currents of Carbendazim were studied. Based on the signal amplification of graphene nanosheets, a novel electrochemical method with high sensitivity for carbendazim was developed. The linear range was from 1.0 to 250.0 ?g L-1, and the detection limit was 0.15 ?g L-1. Finally, this new sensing system was used in lake water samples, and the accuracy was satisfactory.

Resume : Graphene, as a zero band gap material, has opened up various promising applications for electrochemical and electronic devices. Combining graphene with silicon carbide, a semiconductor material, namely the synthesis of graphene/SiC sandwich structures or hybrid nanolaminates can then expand more electronic and electrochemical applications. In this presentation, a novel one-step technique using microwave assisted plasma chemical vapour deposition (MWCVD) will be introduced for depositing 3C-SiC/graphene hybrid nanolaminates. The characterisation of their surface morphology and chemical information with scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy will be summarized. SEM observation shows different growth types (varied thicknesses of graphene and SiC layers) at different MWCVD deposition conditions. The formation/numbers of graphene layers and 3C-SiC is further verified by Raman spectroscopy. Four-point-probe measurement was taken out to achieve information about the conductivity of the different films. Their conductivity improves with an increase of graphene amount inside the hybrid nanolaminates. With help of the transmission electron microscopy investigation, the growth mechanism, growth behaviour and the formation of the nanolaminate structure will be presented. The control of individual layer thickness of both 3C-SiC and graphene will be shown through varying the deposition parameters directly during the MWCVD process. The use of these hybrid nanolaminates for electrochemical applications, such as the capacitor electrodes for super- and pseudocondensators, will be presented in both aqueous and organic solvents.

Resume : Currently, renewable and low-cost electrode materials are being intensively pursued to meet the development of sustainable electrochemical energy-storage systems. Chitin, which is the second most abundant biopolymer throughout the natural world derived from the exoskeletons of arthropods and shells of cephalopods, owns many attractive properties such as renewability, nontoxicity, intrinsically fibrous structure and high content of nitrogen. Herein, the nitrogen-doped amorphous carbon nanofibers (NACF) fabricated by directly pyrolysis of chitin is used as anode material in potassium ion batteries (KIBs) for the first time. The NACF electrode delivers excellent performance, such as high capacity, high rate capability, and stable long cycling life. The superior electrochemical performances are mainly attributed to synergistic effect of the unique one-dimensional porous nanofibers benefiting the transmission of electron/electrolyte, and the N-doped amorphous nanostructure increasing electrical conductivity and active sites. Our work provide a new approach for the preparation of heteroatom-doped carbonaceous materials with unique porous nanofibers microstructure using natural enlightenment, which should inspire us to explore more other advanced materials with value-added attributes by treatment of renewable bio-waste.