红外光谱电化学研究金电极表面上CO2的还原

以碳酸丙烯酯(PrC)为溶剂,高氯酸四丁基胺(TBAP)为电解质,利用电化学及红外光谱电化学开展了金电极上二氧化碳的还原研究。运用现场红外光谱跟踪电化学还原过程反应物及产物的生成和消失。红外光谱电化学循环伏吸法表明,在消耗CO2的同时,金电极上有CO的产生,且伴随有碳酸根的形成。结合电化学和光谱电化学结果,提出了一种电还原机理:在非水介质中,CO2电还原过程中生成了中间体CO2.-,随后CO2.-分别以两个途径进行还原,其一是直接被还原成CO,其二是与CO2结合生成C2O4.-而后歧化成CO以及CO32-。两个反应同时进行,且第一个反应是可逆过程。

FTIR Spectroelectrochemistry Study on the Reduction of CO2 at a Gold Electrode Interface

Electrochemistry and FTIR spectroelectrochemistry methods were used for investigating the reduction of CO₂ on gold surface in propylene carbonate (PrC) including tetrabutyl ammonium perchlorate (TBAP) as electrolyte. By using the infrared spectroelectrochemistry cyclic voltabsorptometry (CVA), it is found that with the decrease of CO₂, the CO and CO₃^2- were produced. Combined with the results obtained from electrochemistry and FTIR spectroelectrochemistry, the electrochemical reduction mechanism of CO₂ in the non-aqueous media is proposed: CO₂^·- was generated firstly, and then CO₂^·- reduced to CO by two pathways. One is electrochemically reduced to CO directly, the other is CO₂^·- radicals reaction with CO₂ to generate C₂O₄^·-, then leading to formation of CO and CO₃^2-. Both of them carried out at the same time the former is reversible process.