胆红素-氯仿体系对氧还原反应的电催化

Electro-catalytic reduction of oxygen by bilirubin-chloroform system

采用循环伏安法、电位阶跃法和旋转圆盘电极研究了胆红素-氯仿体系对氧还原反应的电催化行为．结果表明，氧还原的峰电流随扫描速度增加而增大，还原峰峰Ⅰ（-190mV）的峰电流ip与v^1/2、峰Ⅱ（-550mV）的峰电流ip与v呈线性关系，峰Ⅱ的峰电流与胆红素的浓度在1．0×10^-6-2．0×10^-5mol／L范围内有良好的线性关系．在电极反应过程中氧的还原分两步进行，第一步由O2还原到H2O2（峰Ⅰ），主要受扩散控制，第二步，由于氯仿的疏水作用，H2O2聚集在电极表面被胆红素（BR）催化还原为H2O2（峰Ⅱ），主要受吸附控制．

The electro - catalytic reduction of oxygen by bilirubin - chloroform system was studied using cyclic voltammetry, potential step and rotating disk electrode. The resuits indicate that the peak current of reduction increases with sweep speed. The peak current of peak Ⅰ at - 190 mV has linear relation with the square root of sweep speed,whihle peak current of peak Ⅱ at - 550 mV has linear relation with v. The electro - catalytic reduction current of peak Ⅱ of oxygen vs. the concentration of bilirubin has a good（linear） relation in the range of 1.0 × 10 ^-6 - 2.0 × 10^-5 mol/L. The electro - catalytic reduction of oxygen reaction includes two steps： firstly O2 reduced to H2O2, which is a diffusion - controlled process; then H2O2 reduced to H2O, which is controlled mainly by adsorption.