离子液体中硫氰根在铂电极上吸附行为的SERS研究

利用表面增强拉曼光谱(SERS)研究了室温离子液体1-丁基-3-甲基咪唑氟硼酸盐([BMIM]BF4)中SCN-在Pt电极表面的吸附行为. 研究结果表明, 离子液体中SCN-在较宽的电位范围内吸附在Pt电极上, 且SCN-的吸附方式随着电位区间的变化而变化, 在不同的电位区间内检测到了不同的Stark位移: -0.9~0.4 V约为34 cm-1/V, 对应于S端吸附; -1.6~-1.2 V约为40 cm-1/V, 该区间以N端吸附为主, 中间电位区间为吸附方式的转变区, 且Pt电极在离子液体[BMIM]BF4中的零电荷电位约为-1.1 V(vs. Pt ).

Surface Enhanced Raman Spectroscopic Studies of the Adsorption of Thiocyanate at Pt Electrode in Ionic Liquids

The adsorption behavior of thiocyanate(SCN-) on the Pt electrode in the room-temperature ionic liquids of 1-n-butyl-3-methylimidazolim tetrafluoroborate([BMIM]BF4) was investigated by electrochemical in situ surface enhanced Raman spectroscopy(SERS). The results revealed that SCN- adsorbed onto Pt surface in a wide potential region, and the adsorption behavior of SCN- changed with the variation of the potential. Different Stark effects were observed in different potential regions, i.e. the S—Pt bonding exhibited the Stark shift of 34 cm-1/V over the range from -0.9 V to 0.4V, and Stark shift of 40 cm-1/V over the range from -1.6 V to -1.2 V for the N—Pt interaction. There is a transition region for the S- or N-adsorption between -0.9 V and -1.1 V. The change in the Stark effect in the different potential regions suggests that the potential of zero charge(pzc) of the [BMIM]BF4-Pt system is around -1.1 V(vs. Pt).