Preparation, Characterization And Application Of Electrocatalytic Materials

Electrocatalytic reactions are important aspects of electrochemical investigation. When the electrode reactions occurred in the presence of electrocatalyts, the activation ergegy would be decreased and the reaction rate would be enhanced. In order to find materials with high electrocatalytic activity, the hydrogen evolution electrocatalytic materials, electrocatalytic oxidation to methanol and modified carbon paste electrode were studied.Firstly, La₂O₃ was successfully doped into nickel-cobalt alloy coating on Ti substrate by electrodeposition technology. The surface morphology and microstructure were examined by SEM and XRD, respectively, and the hydrogen evolution property was evaluated by steady-state polarization, Tafel plot and electrochemical impedance spectroscopy. It was found that the incorporated La₂O₃ particles resulted in the improvement of roughness and surface area of the composite coating electrode, and hydrogen evolution potential of nickel-cobalt-La₂O₃ composite coating electrode moved positively around 178 mV at 15.0 mA cm–2 compared with that of nickel-cobalt alloy deposited coating electrode. The proposed materials are promising hydrogen evolution electrocatalytic materials.Nanostructured Pt/C catalyst for methanol electrooxidation was prepared by impregnation method in different water-organic solvents (ethanol, acetone, isopropanol, n-butanol). It was found that the size of Pt particle was varied with water-organic solvents demonstrated by XRD. Its electrocatalytic activity to methanol was evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Due to that the electroactivity of catalyst could be enhanced by adding assistant electrocatalysts, the 4A-zeolite as assistant electrocatalyst was doped into Pt/C catalyst by simple mixing. The corresponding electrocatalytic activity for electrooxidation of methanol was evaluated in alkaline medium by several electrochemical techniques, including cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. It was shown that the electrocatalytic activity of the 4A-zeolite modified Pt/C catalyst was much better than that of the Pt/C catalyst. The increased electrocatalytic activity could be attributed to that the advanced properties of the micrometer 4A-zeolite with nano-porosity could significantly increase the effective electrode surface and facilitate the diffusion of analytes into the film of electrode surface.Carbonized bacterial cellulose based carbon paste electrode (BCPE) was fabricated with nano-dimension carbonized bacterial cellulose (BC) fiber and studied by SEM, cyclic voltammetry and electrochemical impedance spectroscopy. Compared with traditional carbon paste electrode (CPE), a faster electron-transfer kinetics process happened on BCPE in wide scan rate ranges. Moreover, PMo12 was successfully assembled on BCPE surface by cyclic voltametric scanning method. Good stability and catalytic activity to the reduction of nitrite were observed on PMo12/BCPE. This novel carbonaceous materials is prospected to be used in electrocatalysis and other fields due to its mentioned advantages.