Synthesis And Electrochemistry Properties Of H₂O₂ Electroreduction Catalyst

The experiment fabricated silver/nickel catalyst, gold/nickel alloy catalyst, gold and silver/nickel catalyst and MnO2/nickel catalyst by electrodepositing silver, gold, gold and silver alloys and MnO2 on the matrix nickel foam and researched the microstructure and properties of the catalysts by SEM and XRD. The results showed that the structure of the sample was well-distributed. XRD pattern indicated that the structure of the electrode were mixed with a small amount of Mn(OH)2-orientde and contains MnO2. The SEM characterization shows that the MnO2 electrode is made up of some irregular linear structure.The catalysts were studied by electrochemical test. The results showed that each of these three noble metal catalyst represent the best catalytic activity when the hydrogen peroxide concentration is 0.3 mol/L; and it also shows the silver/nickel catalyst scanned in alkali liquid than not scanned has higher catalytic activity:at low concentration (CV) silver /nickel catalyst activity is better; when the concentration of the hydrogen peroxide is 0.2 mol/L, the limiting current can reach 170 mA/cm" up. In high concentrations (0.3-0.4 mol/L), the alloy of gold and silver/nickel compound catalyst is more active. When the hydrogen peroxide concentration of the hydrogen peroxide is 0.4 mol/L, the limiting current can reach 325 mA/cm2. The catalyst made by this method has very good electrochemical properties at room temperature.Their performances for hydrogen peroxide electro-reduction in KOH solution were investigated by cyclic voltammogram and chronoamperometry test. Results revealed that the electrode deposited by cycling the potential for 15min between 0.8 and 1.1V (vs Ag/AgCl) exhibit high activity for electrocatalytic reduction of H2O2 in 3 mol·L-1 KOH solution. A current density of as high as 67 mA·cm-2 was achieved on the MnO2 electrode when hydrogen peroxide concentration was 0.4 mol·L-1,the potential was -0.4 V. Comparing to the nickel foam electrode filled with corresponding powder prepared by other methods, these electrodes show better activity and greater stability, reproducible and the methods of the preparation of them are more simple and convenient.