采用循环伏安与Tafel曲线比较不同阳极的电催化性能

Comparison of Electrocatalytic Performance of Different Anodes with Cyclic Voltammetry and Tafel Curves

采用循环伏安和Tafel曲线两种方法评价了Pt电极、钛基二氧化钌电极(Ti/RuO2)及钛基二氧化锡电极(Ti/SnO2)的电催化氧化性能.结果表明,在500 mg/L的苯酚溶液中,Pt,Ti/RuO2和Ti/SnO2电极氧化苯酚的峰电位依次为0.93,0.95和1.40 V(vsAg/AgCl).Tafel曲线表明,三种电极析氧过电位的顺序依次是Ti/RuO2<Pt<Ti/SnO2,Ti/SnO2电极的Tafel斜率约为0.45 V,且在高电流密度下其析氧过电位较Ti/RuO2电极高1.4 V.以苯甲酸为羟基自由基捕获剂,采用荧光光谱法间接检测了三种电极生成羟基自由基的量.结果表明,.OH生成量的大小与电极的析氧电位高低顺序相一致,Ti/SnO2电极较另两种电极生成的.OH多.

The eletrocatalytic capability of Pt, Ti base RuO2（Ti/RuO2）, and Ti base SnO2（Ti/SnO2） electrodes was evaluated with cyclic voltammetry （CV） and Tafel curves. CV curves of the three electrodes were measured in 500 mg/L phenol solution, and their phenol oxidation peak potentials were around 0.93, 0.95, and 1.40 V （ vs Ag/AgCl）, respectively. The capability of direct electrocatalytic oxidation of phenol lied in the sequence of Pt〈 Ti/SnO2 〈 Ti/RuO2. The Tafel curves were measured in 0.1 mol/L H2SO4 and the results showed that the oxygen evolution overpotentials of the three electrodes increased in the order Ti,/RuO2 〈 Pt 〈 Ti/SnO2. The slope of the Tafel curve of the Ti/SnO2 electrode was about 0.45 V, and at high current density, the oxygen evolution overpotential was 1.4 V higher than that of the Ti/RuO2 electrode. Fluorescence spectroscopy was employed to examine the electrode performance of producing ·OH with benzoic acid as the·OH capture agent. The results indicated that the amount of ·OH corresponded to the oxygen evolution overpotential of the electrodes. There were more ·OH radicals production during the electrocatalytic process on the Ti/SnO2 electrode than that on the other two electrodes.