碱性介质中正丁醇在铂电极上吸附和氧化的电化学原位FTIR反射光谱和EQCM研究

EQCM and in situ FTIR Studies on the Adsorption and Oxidation of 1-Butanol at a Platinum Electrode in Alkaline Media

运用电化学循环伏安(CV)、原位FTIR反射光谱和电化学石英晶体微天平(EQCM)等方法研究了碱性介质中正丁醇在Pt电极表面吸附和氧化行为。结果表明:正丁醇电氧化过程与溶液酸碱性有着密切的关系。酸性介质中正丁醇在Pt电极上的CV曲线有2个正向氧化峰,而碱性介质中只有1个正向氧化峰,第2个氧化峰的消失可能是由于碱性介质中Pt电极表面钝化引起的。原位FTIR反射光谱检测到,在实验条件下,碱性介质中正丁醇电氧化过程的最终产物只有丁酸根。EQCM研究还从电极表面质量定量变化的角度提供了正丁醇反应机理的新数据。

The adsorption and oxidation of 1-butanol in alkaline media on a platinum electrode were investigated mainly by EQCM and in situ FTIR spectroscopy. The experimental results demonstrate that the electrooxidation of 1-butanol is closely relative to solution acidity. Since no chemically adsorbed species, such as CO, were evidenced by in situ FTIR spectroscopy, the adsorption of 1-butanol or its dissociative products on Pt surface is suggested by EQCM and CV data. Only one current peak of 1-butanol oxidation in PGPS was detected at -0.23 V/SCE, which illustrated the disappearance of the second current peak due to Pt electrode passivation in alkaline media. The final product of 1-butanol oxidation is only butyric acid anion under experimental condition. It may therefore be suggested that the main reaction occurring at the electrode is the oxidation of 1-butanol to butyric acid anion. The EQCM studies provide quantitative results of surface mass variation and have shed light on elucidating 1-butanol oxidation.