碳酸丙烯酯/季铵盐溶液中H_2O对CO_2电还原反应的影响作用及机理分析  

Water effects on CO_2 electro-reduction in propylene carbonate/tetrabutylammonium perchlorate solution

作　　者：沈风霞[1] 陈天友[1] 李青远[2] 宋宁[1] 贾友见[1] 施锦[1,2] 

机构地区：[1]昆明理工大学冶金与能源工程学院,云南昆明650093 [2]昆明理工大学省部共建复杂有色金属资源清洁利用国家重点实验室,云南昆明650093

出　　处：《化学研究》2017年第4期474-481,共8页Chemical Research

基　　金：国家自然科学基金(51164020)

摘　　要：设计了一种新型双室隔膜电解池,可以在碳酸丙烯酯(PC)/四丁基高氯酸铵(TBAP)电解液中,将CO_2电还原为CO.由于CO_2电还原反应本身有H_2O生成,深入探究了H_2O对有机电解液电化学性能和电极反应过程的影响作用及相关机理.结果表明,当PC/TBAP中含有H_2O时,电解液电导率增大,黏度降低,CO_2溶解性增强.由于碳酸丙烯酯具有疏水性,当含H_2O量超过6.8%时,H_2O从PC/TBAP中分层析出,电解液的性质不会因水的积累而发生改变.反应过程中,H_2O对反应中间体(CO_2^(·-)自由基)具有稳定作用,使得过电位降低、电流密度升高.在PC/TBAP/6.8%H_2O中电还原CO_2时,生成CO的最高电流效率达到89%,电流密度达到9.18 mA/cm^2,电极不中毒,电化学反应可以稳定进行.A novel two-chamber electrolysis cell was studied for electrochemical reduction of CO_2 into CO in propylene carbonate（PC）/tetrabutylammonium perchlorate（TBAP） electrolyte.Because the electrochemical reduction of CO_2 into CO naturally produce water,the presence of water in the organic electrolyte is inevitable.This work has focused on the investigation of the water effects on the performance of the organic electrolyte and the process of CO_2 reduction.The experiment results showed that the presence of water in PC/TBAP had a positive effect on the performance of the electrolyte,such as increasing the conductivity,decreasing the viscosity and improving the CO_2 solubility.When the water content is more than 6.8%,water is separated from the organic electrolyte automatically and the property of electrolyte is not changed significantly.The electrochemical reduction of CO_2 into CO was studied in the PC/TBAP electrolyte with containing 6.8% water,the Faradic efficiency reached 89% and the current density reached 9.18 m /cm^2.During the long term electrolysis process,deactivation was not found on the surface of Au electrode.

关 键 词：双室隔膜电解池 二氧化碳电还原 碳酸丙烯酯 金电极 

分 类 号：O646[理学—物理化学]