铜电极上CN-、SCN-电化学行为的现场红外反射吸收光谱研究

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+0.5 mol L~(-1)NaF/Cu体系, 电极电势在-1.60至0.30 V(相对SCE)范围内, 2030—2230 cm~(-1)范围内可得到三个吸收峰, 位置分别为2076, 2094和2170 cm~(-1)。2076和2170 cm~(-1)峰分别对应于溶液中CN~-和表面沉积难溶化合物CuCN。2094 cm~(-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0.5 molL~(-1)NaSCN+0.5 molL~(-1)NaF/Cu体系, 在上述电势范围内可得到2060, 2177和2170 cm~(-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。

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

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 2170 cm~(-1) were recorded within the wavenumber range 2030-2230 cm~(-1) in 0.5 molL~(-1) NaCN+0.5 molL~(-1) NaF. The bands near 2070 and 2170cm~(-1) were due to solution species CN~- and surface deposited CuCN respectively. The band near 2094 cm~(-1) was attributed to absorbed CN~- and complex Cu(CN)_3~(2-). In 0.5 mol L~(-1) NaSCN+0.5 mol L~(-1) NaF, three bands near 2060, 2117 and 2170 cm~(-1) were observed in the potential range metioned above, and attributed to the IR absorption of solution species SCN~- (2060 cm~(01)), absorbed SCN~- (2117 cm~(-1)) and CuNCS (2170 cm~(-1)) which was the product of electrode reaction.