新型铜配合物修饰热解石墨电极上的氧电催化还原

Electrocatalytic Reduction of Oxygen at Pyrolytic Graphite Electrode Modified with Novel Copper(Ⅱ) Complex

采用新型单核铜配合物高氯酸咪唑N-2-羟基乙基二乙烯三胺合铜(Ⅱ)(Cu[L(ImH)](ClO4)2)修饰热解石墨(PG)电极表面制得了Cu[L(ImH)]/PG电极,并采用循环伏安法和电位阶跃实验研究了该电极对氧的催化还原作用.结果表明,该电极在中性和碱性条件下对氧气的催化还原具有良好的稳定性,还原峰电流随电位扫描速度的增大而增强,Ip^v1/2呈线性关系.根据电位阶跃实验的I^t-1/2曲线,计算出电极反应的电子转移数约为4,推断氧气在该电极上的还原是经历了4电子过程还原为水,催化机理属于混合控制的ECE(E电极反应,C化学反应)过程.

A novel five-coordinated copper （ Ⅱ ） complex （Cu [ L （ImH） ] （ ClO4 ）2 ）, which was self-assembled with imidazole, Cu^2＋ center, and 2- [ bis （2-aminoethyl） amino ] ethanol （L）, was synthesized. The ligand L bearing an O atom at the hydroxyethyl arm with proper flexibility provided enough variability to adapt the different configuration requirement of Cu^2＋/Cu^＋ in the redox process. The pyrolytic graphite （PG） electrode modified with the Cu [ L（ImH） ] （ClO4） 2 complex was constructed. The electrochemical behavior and electrocatalytic activity of the Cu [ L （ImH）]/PG electrode for oxygen reduction were studied by cyclic voltammetry and chronoamperometry. The Cu [ L（ImH） ]/PG electrode exhibited high electrocatalytic activity and stability for oxygen reduction. The reduction current increased with the increase in scan rate, and the plot of Ip to v^1/2 was linear. According to the results of potential step chronoamperometry, the electrocatalytic mechanism of oxygen reduction at the modified electrode might be similar to the ECE （E： electrode reaction, C： chemical reaction） process, the number of electron transfer in the reduction process was about 4, and the oxygen was finally reduced to 820 at the modified electrode.