应用超微电极和粉末微电极技术研究有机溶剂和正极材料对氧气还原反应和氧气生成反应的影响

摘要

采用碳纤维超微电极分别研究了O2在二甲基亚砜、乙腈和四甘醇二甲醚3种有机溶剂中的电化学反应,结果表明,当阳离子只含四丁胺离子时,反应呈可逆的一电子转移;而阳离子只含锂离子时,O2的还原和氧化均经历了多电子转移过程.利用超导炭黑和乙炔黑制作粉末微电极进行电化学测试,结果表明,在这2种正极材料上,氧气还原反应(ORR)过程相似,氧气生成反应(OER)过程区别明显.此外,Tafel分析结果表明,对于不同有机溶剂和正极材料,O2还原均经历了初始的一电子转移步骤.%Carbon fiber ultra-microelectrode was used to study the electrochemical reactions of O2 in dimethyl sulfoxide, acetonitrile and tetraethylene glycol dimethyl ether.The results suggested that in {tetrabutyl-ammonium-ion(TBA+)-containing electrolytes, the electrochemical reactions were reversible reactions of one-electron transfer;while in lithium-ion(Li+)-containing electrolyte, multiple-electrons transfer occurred during the oxygen reduction reaction(ORR) and oxygen evolution reaction(OER).Powder microelectrodes of super P and conductive acetylene black were used as working electrodes to conduct electrochemical experiments.The results showed the ORRs were similar, but the OER had differences on these two materials.Besides, Tafel analyses indicated that during the ORR, one-electron transfer always took place at first whether in different non-aqueous solvents or on different cathodes.