离子液体中钯电极上氧分子电化学还原反应初探:水的影响

A Preliminary Study of Oxygen Reduction Reaction on Palladium Electrode in Ionic Liquid System:Effect of Water

本文通过循环伏安法分别研究了在酸性水溶液与离子液体1-丁基-3-甲基咪唑四氟硼酸盐([Bmim]BF4)中钯电极上的氧还原反应(ORR),并探究了离子液体中质子供体(水)的引入对氧电还原反应的影响.结果表明,与酸性水溶液中钯电极上氧还原反应的4电子途径不同,在质子惰性的[Bmim]BF4离子液体中钯电极上的氧还原是通过1电子途径进行,还原生成离子液体中能稳定存在的O2●-,且该反应有较好的可逆性.而在离子液体中引入少量水后,氧还原反应逐渐向不可逆的2电子途径转化,生成过氧化物.

In order to study the electrochemical reduction of oxygen molecule on palladium electrode in ionic liquid,the reduction of oxygen on palladium electrode in H2SO4 aqueous solution as well as ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate（[Bmim]BF4）system has been studied using cyclic voltammetry.The effect of the proton donor（water）with different content has also been studied.The results indicate that the oxygen reduction reaction can be ascribed to a one-electron quasi-reversible process generating stable superoxide O2^●-in aprotic[Bmim]BF4.Upon water addition,the electro-reduction of O2 changes from a one-electron quasi-reversible process to two-electron irreversible process generating peroxide.It is significantly different from the situation in H2SO4 solution,in which the reduction of O2 occurs via four-electron transfer electrode reaction.