卟啉化合物对氧电极反应的催化作用（Ⅱ） 溶液pH值和阴离子对经热处理的四对甲氧基苯基卟啉钻催化活性的影响及反应机理的讨论

卟啉化合物对氧电极反应的催化作用（Ⅱ） 溶液pH值和阴离子对经热处理的四对甲氧基苯基卟啉钻催化活性的影响及反应机理的讨论 THE ELECTROCATALYSIS OF OXYGEN REDUCTION REACTION BY METALLOPORPHYRINS * （Ⅱ） The effects of pH and anions upon catalytic activity of heat-treated Co meso-tetra-（ P-OCH 3 ）- phenylporphyrins and the mechanism of reaction 李长明 first-author 王宗礼 查全性 建立了适合于研究粉末催化剂电极过程的软嵌式超薄电极技术,并研究了在经热处理的四对甲氧基苯基卟啉钴/光谱纯石墨粉表面上氧的还原反应,特别是溶液pH值和阴离子的影响。实验结果表明,该催化剂能在广泛pH范围内适用,主要催化二电子反应,随pH值增大,发生氧还原反应的电位负移,但电极反应的可逆性增大,同时阴离子的阻化效应减小。讨论了催化剂上氧还原反应的机理。在具有不同pH值的溶液中,反应机理不尽相同,但控制步骤一般都是第一个电子的转移步骤。根据所假设的机理,较好地解释了所得的实验结果。 The technique of fabricating disc electrode with ultra-thin layer of powdered catalyst has been established to study the electrocatalysis of oxygen reduction reacton by heat-treated Co meso-tetra-（P-OCH 3 ）phenylporphyrins with the RRDE method. Results of experiments demonstrated that the reaction is carried out mainly through the two-electron path. With the rise of pH, the reversibility of the reduction wave improves, such as the Cl- anion, could inhibite somewhat the rate of oxgen reduction, especially in acidic solutions. Based on the change of Tafel slope with pH, the nechanism of reaction in solutions of different pH has been postulated. In general, the rate of reaction seems to be the transfer of super oxygen ions or hadrated super oxygen ions. 中国科学院科学基金 1983-04-01 2021-04-01 4