Deactivation Mechanism of Au Electrode in Electrochemical Reduction of CO2
1. Faculty of Science, Kunming University of Science and Technology, Kunming 650500, China;
2. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China
Abstract The working electrode might get inactivate easily in the process of electrochemical reduction of CO2 to CO in aqueous solution. The effects of the deactivation reasons of the Au electrode and the decrease of electrode activity on the reaction during the electrochemical reduction of CO2 in KHCO3 aqueous solution, and the surface of Au electrode were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS).The results showed that a small amount of impurities composed of C graphite and a little of Fe and Zn adsorbed on the surface of the Au electrode. The electrochemical kinetic characteristics of CO2 reduction on Au electrode were studied using Tafel curve, Electrochemical impedance spectroscopy(EIS), Linear sweep curve, Potentiostatic electrolysis, and gas chromatographic. As a result, with the reaction going on, the equilibrium potential of CO2 conversion to CO shifted to negative, the electron transfer resistance rised up, the exchange current density reduced continuously, and the faradaic efficiency of CO decreased rapidly, which indicated that C graphite and metal adsorbed on the electrode decreased the electrocatalytic activity of Au electrode, and hindered the CO2 reduction.
Wang Qin1,Wang Xiaochun2,Yang Dongwei2 et al. Deactivation Mechanism of Au Electrode in Electrochemical Reduction of CO2[J]. 化学反应工程与工艺, 2015, 31(4): 352-358.
Wang Qin1,Wang Xiaochun2,Yang Dongwei2 et al. Deactivation Mechanism of Au Electrode in Electrochemical Reduction of CO2[J]. 化学反应工程与工艺, 2015, 31(4): 352-358.
