卟啉配合物修饰玻碳电极上抗坏血酸的催化电氧化

摘要

研究了抗坏血酸在四(邻硝基苯基)四苯并卟啉的Mn3+、Fe3+、Co2+和Ni2+的配合物(简记为MP)修饰玻碳电极上的电化学氧化。结果表明它们对抗坏血酸的电化学氧化均具有明显的催化活性，其活性顺序为Fe3+P＞Mn3+P＞Ni2+P＞Co2+P。动力学和反应机制的研究表明铁卟啉修饰电极上抗坏血酸的电化学氧化为一前置反应控制的二电子配位催化反应。抗坏血酸和氢离子的反应级数分别为1和-2。反应为不可逆，其Tafel斜率为60 mV/decade。%The catalytic behavior of Mn3 +, Fe3 +, Co2 +, and Ni2 + coordination compounds with meso- tetra (o - nitrophenyl) tetrabenzoporphyrin(MP) was studied for the electrochemical oxidation of ascorbic acid on glassy carbon electrode. The MP's exhibit significant catalytic effect on the electrochemical oxidation of ascorbic acid and are sequenced as: Fe3 +P＞Mn3 +P＞Ni2 +P ＞ Co2 + P.The data of dynamics on Fe3 + P shows that the reaction follows a two- electron coordination catalytic model, which is irreversible and limited by the reaction between ascorbic acid and Fe3+P on the electrode surface. The reaction orders in ascorbic acid and H+ ion are 1 and - 2, respectively, and the Tafel slope is 60 mV/decade.