Preparation And Performance For Oxygen Evolution Of Ti-based Noble Metal Oxides Electrodes

As a clean, safe, and efficient secondary energy, hydrogen has already become a research focus by scholars at home and abroad. There is potential for development of hydrogen production by water electrolysis. Anodic overpotential is one of the main reasons for low efficiency of industrial water electrolysis. Therefore , the study of anode material with high activity, long life, low-cost has a practical significance for large-scale industrial electrolysis hydrogen.In this thesis, RuO2(x)-Co3O4(1-x)/Ti composite electrode was prepared by thermal decomposition technology in comparison to the catalytic activity and stability of RuO2/Ti and Co3O4/Ti to improve the life time and reduce cost of Ti-based metal oxide anode. Firstly, effect of various calcination temperatures on the structure, surface morphology, stability and electrocatalytic properties of the surface active coating of electrode by SEM, EDX and XRD was investigated. Electrocatalytic activity in 1.0mol/L KOH solution was studied recording open-potential, cyclic voltammetry and polarisation curve. Secondly, the role of RuO2 content on RuO2(x)-Co3O4(1-x)/Ti electrode was discussed by the eletrocatalytic properties and accelerated life of the electrode. Simultanously, rare earth doped RuO2(0.3)-Co3O4(0.7) /Ti electrode were studied in detail. At last, the oxygen evolution reaction mechanism of the electrode in alkaline solution was investigated and established the dynamic model of oxygen evolution.Results indicated that the temperature of thermal treatment had remarkable influence on the properties of electrode. When the surface active coating parepared at 400℃, it showed good electrocatalytic performance and long accelerated life. The appropriate content of RuO2 could increase electrocatalytic activity and stability. Mixed oxide electrodes with 50mol% RuO2 showed the optimal performance.Experimental results showed that doping of rare earth was in favor of grain refining, could increase the active surface area of the coating and help to enhance the electrical conductivity and electrocatalytic ability of electrodes. Rare earth doping with right amount could promote the surface enrichment of Ru element and thereby increase the number of surface-active point. Catalytic performance of the RuO2(0.3)-Co3O4(0.7)/Ti mixed oxide electrodes containing 10:3 Ce doped, 10:1 La doped or 20:1 Nd doped content was the best.Mechanism of catalytic reaction of the oxygen evolution of metal composite oxide electrode in alkaline solution was proposed. Kinetic parameters calculated by above-mentioned mechanism were consistent with the experimental data, which indicated that the mechanism could give a reasonable explanation for the dynamics of the prepared electrodes.