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用氢气泡动态模板法在铜基底上沉积锡制备了一种新型锡电极。采用SEM、EDS和XRD对多孔锡沉积层进行表征,并对其催化CO_2电化学还原制甲酸的性能进行了研究。SEM结果表明多孔锡沉积层具有自组织的蜂窝状三维多孔结构,同时EDS分析表明电极表面无杂质。XRD表征表明在基底和Sn沉积层交界处有Cu_5Sn_6合金生成,加强了两者之间的连接。采用不同扫描速率下循环伏安曲线法测试电化学表面积,多孔锡电极的电化学表面积大约是普通锡片电极的6倍。电极的循环伏安测试结果表明,多孔锡电极比普通锡片电极具有更高的电流密度,更正的起峰电位,说明具有多孔结构的电极对CO_2电化学还原反应具有更高的活性。通过考察KHCO_3浓度、还原电位对还原过程的影响,确定KHCO_3浓度为0.5 mol/L,还原电位为-1.7 V vs.SCE时,甲酸的电流效率可达73.9%。由此可见,多孔结构电极材料能有效地提高CO_2电还原的催化效果。
A new type of tin electrode was prepared by depositing tin on copper substrate by hydrogen bubble dynamic template method. The porous tin deposits were characterized by SEM, EDS and XRD, and their catalytic properties for the catalytic reduction of formic acid by CO 2 were also studied. SEM results show that the porous tin deposits have a self-organized honeycomb three-dimensional porous structure, while EDS analysis shows that the electrode surface is free of impurities. XRD characterization shows that Cu_5Sn_6 alloy is formed at the interface between the substrate and the Sn deposit, strengthening the connection between the two. Electrochemical surface area was measured by cyclic voltammetry at different scan rates. The electrochemical surface area of porous tin electrode was about 6 times that of common tin electrode. The results of cyclic voltammetry showed that the porous tin electrode has a higher current density and a higher peak potential than the common tin electrode, indicating that the electrode with porous structure has a higher activity for electrochemical reduction of CO_2. The effect of KHCO 3 concentration and reduction potential on the reduction process was investigated. The current efficiency of formic acid was 73.9% when the concentration of KHCO 3 was 0.5 mol / L and the reduction potential was -1.7 V vs. SCE. Thus, the porous structure of the electrode material can effectively improve the catalytic effect of CO 2 reduction.