铜电极上CN^-、SCN^-电化学行为的现场红外反射吸收光谱研究

IN-SITU FTIR REFLECTION-ABSORPTION SPECTROSCOPIC STUDIES OF CYANIDE AND THIOCYANATE ON COPPER ELECTRODE

本文用循环伏安法和现场红外光谱方法研究了铜电极上CN^-和SCN^-的电化学行为。对于0.5mol^(-1)L^(-1)NaCN+0.5mol L^(-1)NaF/Cu体系,电极电势在-1.60至0.30V(相对SCE)范围内,2030—2230cm^(-1)范围内可得到三个吸收峰,位置分别为2076,2094和2170cm^(-1)。2076和2170cm^(-1)峰分别对应于溶液中CN^-和表面沉积难溶化合物CuCN。2094cm^(-1)峰是吸附态CN^-和溶液中配合物Cu(CN)_3~2二物种的红外吸收叠加。对于0.5molL^(-1)NaSCN+0.5molL^(-1)NaF/Cu体系,在上述电势范围内可得到2060,2177和2170cm^(-1)三个红外吸收峰,分别对应于溶液中的SCN^-,吸附态的SCN^-和表面难溶化合物CuNCS。

The behaviors of cyanide and thiocyanate on copper electrode were studied using cyclic voltammetry and in-situ FTIR spectroelectrochemistry. When potential was shifted from -1.60 to 0.30V(vs.SCE), three bands near 2076, 2094, and 2170cm^(-1) were recorded within the wavenumber range 2030—2230cm^(-1) in 0.5molL^(-1) NaCN+0.5molL^(-1) NaF. The bands near 2070 and 2170cm^(-1) were due to solution species CN^- and surface deposited CuCN respectively. The band near 2094cm^(-1) was attributed to absorbed CN^- and complex Cu(CN)_3^(2-). In 0.5molL^(-1) NaSCN+0.5molL^(-1) NaF, three bands near 2060, 2117 and 2170cm^(-1) were observed in the potential range metioned above, and attributed to the IR absorption of solution species SCN-(2060 cm^(-1)), absorbed SCN-(2117cm^(-1)) and CuNCS(2170cm^(-1)) which was the product of electrode reaction.