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High Electrocatalytic Activity (high + electrocatalytic_activity)
Selected AbstractsNitrogen-Doped Ordered Mesoporous Graphitic Arrays with High Electrocatalytic Activity for Oxygen Reduction,ANGEWANDTE CHEMIE, Issue 14 2010Ruili Liu Dr. Durch eine metallfreie Prozedur zugänglicher stickstoffdotierter geordneter mesoporöser Graphit (NOMGAs) für die Sauerstoffreduktion (ORR) überzeugt durch eine höhere elektrokatalytische Aktivität als ein käuflicher Pt-C-Katalysator (siehe Diagramm), eine ausgezeichnete Langzeitbeständigkeit und eine Verminderung von Übertrittseffekten. Als Ursache dieser Leistungsfähigkeit werden in die Graphitstruktur integrierte Stickstoffatome diskutiert. [source] High Performance Carbon-Supported Core@Shell PdSn@Pt Electrocatalysts for Oxygen Reduction ReactionFUEL CELLS, Issue 4 2010W. Zhang Abstract In this report, a low-cost and high performance PdSn@Pt/C catalyst with core,shell structure is prepared by two-stage route. X-ray diffraction (XRD) and transmission electron microscopy (TEM) examinations show that the composite catalyst particles distribution is quite homogeneous and has a high surface area and the PdSn@Pt/C catalyst has an average diameter of ca. 5.6,nm. The oxygen reduction reaction (ORR) activity of PdSn@Pt/C was higher than commercial Pt/C catalyst. Catalytic activity is studied by cyclic voltammetry. High electrocatalytic activities could be attributed to the synergistic effect between Pt and PdSn. [source] Copper Oxide , Graphite Composite Electrodes: Application to Nitrite SensingELECTROANALYSIS, Issue 1 2007Biljana, ljuki Abstract A simple method for the modification of carbon powder with copper oxides is presented. Carbon powder is impregnated with copper(II) nitrate by stirring carbon powder in copper(II) nitrate solution for 1 hour and subsequently thermally treated at 823,K. The modified carbon powder was characterized using electrochemical and spectroscopic techniques. The existence of both copper(I) and copper(II) oxides have been established. The copper oxide modified carbon powder was used for preparation of composite electrodes, and the electrochemical and electrocatalytic behavior of the resulting composite electrodes was studied. The copper oxide modified carbon powder , epoxy composite electrodes showed a high electrocatalytic activity for the nitrite detection in aqueous media, with the detection limit comparable or lower than detection limits obtained with other electrochemical sensors. [source] Self-Assembled Graphene,Enzyme Hierarchical Nanostructures for Electrochemical BiosensingADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Qiong Zeng Abstract The self-assembly of sodium dodecyl benzene sulphonate (SDBS) functionalized graphene sheets (GSs) and horseradish peroxidase (HRP) by electrostatic attraction into novel hierarchical nanostructures in aqueous solution is reported. Data from scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction demonstrate that the HRP,GSs bionanocomposites feature ordered hierarchical nanostructures with well-dispersed HRP intercalated between the GSs. UV-vis and infrared spectra indicate the native structure of HRP is maintained after the assembly, implying good biocompatibility of SDBS-functionalized GSs. Furthermore, the HRP,GSs composites are utilized for the fabrication of enzyme electrodes (HRP,GSs electrodes). Electrochemical measurements reveal that the resulting HRP,GSs electrodes display high electrocatalytic activity to H2O2 with high sensitivity, wide linear range, low detection limit, and fast amperometric response. These desirable electrochemical performances are attributed to excellent biocompatibility and superb electron transport efficiency of GSs as well as high HRP loading and synergistic catalytic effect of the HRP,GSs bionanocomposites toward H2O2. As graphene can be readily non-covalently functionalized by "designer" aromatic molecules with different electrostatic properties, the proposed self-assembly strategy affords a facile and effective platform for the assembly of various biomolecules into hierarchically ordered bionanocomposites in biosensing and biocatalytic applications. [source] Synthesis of Nanohole-Structured Single-Crystalline Platinum Nanosheets Using Surfactant-Liquid-Crystals and their Electrochemical CharacterizationADVANCED FUNCTIONAL MATERIALS, Issue 4 2009Tsuyoshi Kijima Abstract Nanohole-structured single-crystalline Pt nanosheets have been synthesized by the borohydride reduction of Na2PtCl6 confined to the lyotropic liquid crystals (LLCs) of polyoxyethylene (20) sorbitan monooleate (Tween 80) with or without nonaethylene-glycol (C12EO9). The Pt nanosheets of around 4,10,nm in central thickness and up to 500,nm or above in diameter have a number of hexagonal-shaped nanoholes ,1.8,nm wide. High-resolution electron microscope images of the nanosheets showed atomic fringes with a spacing of 0.22,nm indicating that the nanosheets are crystallographically continuous through the nanoholed and non-holed areas. The inner-angle distributions for the hexagonal nanoholes indicate that the six sides of the nanoholes are walled with each two Pt (111), Pt (11) and Pt (010) planes. The formation mechanism of nanoholed Pt nanosheets is discussed on the basis of structural and compositional data for the resulting solids and their precursory LLCs, with the aid of similar nanohole growth observed for a Tween 80 free but oleic acid-incorporated system. It is also demonstrated that the nanoholed Pt nanostructures loaded on carbon exhibit fairly high electrocatalytic activity for oxygen reduction reaction and a high performance as a cathode material for polymer-electrolyte fuel cells, along with their extremely high thermostability revealed through the effect of electron-irradiation. [source] Electrocatalytic Oxidation of Nitrite at Gold Nanoparticle- polypyrrole Nanowire Modified Glassy Carbon ElectrodeCHINESE JOURNAL OF CHEMISTRY, Issue 12 2009Jing Li Abstract A novel chemically modified electrode based on the dispersion of gold nanoparticles on polypyrrole nanowires has been developed to investigate the oxidation behavior of nitrite using cyclic voltammetry, differential pulse voltammetry and chronoamperometry techniques. The diffusion coefficient (D), electron transfer coefficient (,) and charge transfer rate constant (k) for the oxidation of nitrite were determined. The modified electrode exhibited high electrocatalytic activity toward the oxidation of nitrite. The catalytic peak current was found to be linear with nitrite concentrations in the range of 8.0×10,7,2.5×10,3 mol·L,1 with a detection limit of 1.0×10,7 mol·L,1 (s/n=3). The proposed method was successfully applied to the detection of nitrite in water samples with obtained satisfactory results. Additionally, the sensor also showed excellent sensitivity, anti-interference ability, reproducibility and stability properties. [source] Electrocatalytic Reduction of NAD+ at Multi-walled Carbon Nanotubes Modified ElectrodeCHINESE JOURNAL OF CHEMISTRY, Issue 4 2005Chen Li-Ming Abstract The cyclic voltammetric (CV) behaviors of NAD+ were studied with a multi-walled carbon nanotubes (MWNTs) modified glassy carbon (GC) electrode. In 0.05 mol/L tris(hydroxymethyl)aminomethane-HCl (Tris-HCl) buffer solution (pH=6.9), the MWNTs modified electrode showed high electrocatalytic activity toward reduction of NAD+. The electroreduction of NAD+ was an irreversible diffusion controlled process. The cathodic peak current in-creased linearly with increasing the concentration of NAD+. The influences of scan rate, temperature and concentration were also investigated. [source] Inorganic-Organic Hybrid 18-Molybdodiphosphate Nanoparticles Bulk-modified Carbon Paste Electrode and Its ElectrocatalysisCHINESE JOURNAL OF CHEMISTRY, Issue 8 2002Xiu-Li Wang Abstract A kind of inorganic-organic hybrid 18-molybdodiphosphate nanoparticles ([(C4H9)4N]6P2Mo18Q62·4H2O) was firstly used as a bulk-modifier to fabricate a three-dimensional chemically modified carbon paste electrode (CPE) by direct mixing. The electrochemical behavior of the solid nanoparticles dispersed in the CPE in acidic aqueous solution was characterized by cyclic and square-wave voltammetry. The hybrid 18-molybdodiphosphate nanoparticles bulk-modified CPE (MNP-CPE) displayed a high electrocatalytic activity towards the reduction of nitrite, bromate and hydrogen peroxide. The remarkable advantages of the MNP-CPE over the traditional polyoxometalates-modified electrodes are their excellent reproducibility of surface-renewal and high stability owing to the insolubility of the hybrid 18-molybdodiphosphate nanoparticles. [source] | ||||||||||