中文摘要：

电催化还原二氧化碳制备甲酸是备受关注的热点问题。而电极材料是决定还原效率的重要因素。本文通过电沉积方法在泡沫铜上直接制备纳米结构硫化亚铜薄膜,并采用扫描电镜（SEM）、X射线衍射（XRD）对其结构性能进行了系统研究。以硫化亚铜作为阴极电催化材料、0.5 mol·L^–1 1-丁基-3-甲基咪唑四氟硼酸盐的乙腈溶液为电解液,在该体系中可高效催化转化二氧化碳为甲酸。结果表明,这一电解体系可有效实现电化学反应,甲酸的法拉第效率（FEHCOOH）可以达到85%,同时甲酸还原电流密度可达到5.3 mA·cm^–2。

英文摘要：

The electrocatalytic reduction of CO2 to HCOOH is an interesting topic and the efficiency usually depends strongly on the materials of the electrodes. Herein, nanostructured Cu2S on Cu-foam was prepared by electro-deposition method and characterized by means of scanning electron microscope （SEM） and X-ray diffraction （XRD）. The Cu2S/Cu-foam electrode was used for the first time in the electrocatafytic reduction of CO2 to HCOOH, and acetonitrile （MeCN） with 0.5 mol.L^-1 1-butyl-3- methylimidazolium tetrafluoroborate （BmimBF4） was used as the electrolyte. It was demonstrated that the electrolysis system was very efficient for the electrochemical reaction, and faradaic efficiency of HCOOH （FEHCOOH） and reduction current density could reach 85% and 5.3 mA· cm^-2, respectively.