蒽醌/聚吡咯复合膜修饰电极的电化学行为和电催化活性

Electrochemical Behavior and Electrocatalytic Activity of Glassy Carbon Electrode Modified by Anthraquinone/Polypyrrole Composite Film

在水溶液中制备了掺杂蒽醌磺酸盐(AQS)的聚吡咯(PPy)/玻碳复合膜修饰电极,采用循环伏安法和旋转圆盘电极技术研究了该修饰电极在不同pH值溶液中的电化学行为以及在pH=5.5的磷酸盐缓冲溶液中对氧还原反应的电催化性能和动力学.结果表明,与裸玻碳电极相比,PPy膜的存在不仅降低了AQS的反应电位和峰电位差,而且增大了其氧化还原反应的峰电流,H2AQ/HAQ-氧化还原对的电离常数为9.5.AQS/PPy膜修饰电极上氧的还原主要是两电子还原为H2O2的不可逆过程,H2AQ对氧还原反应起主要催化作用,还原过程符合异相氧化还原催化机理.该修饰电极具有良好的电化学重现性.

Conductive and functional polypyrrole （PPy） film was prepared by incorporation of anthraquinone- sulphonate （AQS） as dopant during the electropolymerization of pyrrole on a glassy carbon electrode in aqueous solution. The electrochemical behavior of AQS in PPy matrix in various pH buffer solutions and electrocatalytic reduction of oxygen on the resulting polymer film at the optimized pH of 5.5 were studied by using cyclic voltammetry （CV） and rotating disk electrode （RDE） technique. The results showed that PPy not only lowed the AQS reaction potential and the peak potential separation but also increased the redox peak currents. The value of ionization constant for H2AQ/HAQ^- is 9.5. The CV and RDE studies showed the involvement of two electrons in oxygen reduction and H2AQ is responsible for the enhanced catalytic activity. The catalytic reaction is in agreement with an electrochemical-chemical mechanism. The AQS/PPy composite film-modified electrode was found to exhibit reproducible results.