Au／Nafion电极制备及其苯．水体系电化学性能研究

PREPARATION AND PERFORMANCE OF Au /Nafion ELECTRODE IN BENZENE-WATER ELECTROLYTIC HYDROGENATION

利用电化学、电学等手段研究利用浸渍-还原技术在Nafion膜上制备Au电极的方法,考查Au络合物浸渍时间、还原剂浓度、还原温度等因素对Au/Nafion电极性能的影响。研究发现:较长的浸渍时间、较低的还原剂浓度和较高的还原温度下所制备的电极活性较好,同时以Na2SO3作为还原剂时,可得到表面Au颗粒均匀堆积的Au/Nafion复合电极。对比利用浸渍-还原技术制备的Pt/Nafion电极和浸渍-还原法制备的Au/Nafion电极在水-苯体系电化学加氢反应中的电极活性。结果表明:苯在阴极的加氢反应主要产物为环己烯和环己烷,且在高阴极过电势下主要生成环己烷;利用Au/Nafion电极实现苯在阴极的加氢还原反应总电流效率可达40%~90%(-1.6^-0.4V vs SCE),析氢副反应在Au/Nafion电极上得到较好抑制。

Preparation of SPE electrode plays the important role in the hydrogen storage process with liquid organic hydride. The preparation of Au/Nafion electrodes by impregnation-reduction method was studied by electrochemical and electrical methods. The impact of various factors such as Au complexes impregnation time, reductant concentra- tion and reduction temperature on the Au/Nafion electrodes＇ performance was investigated. The studies found that the electrodes with the longer the soaking time, lower reductant concentration and the higher the reduction tempera- ture have better activity and Au particles can be uniformly stacked on the surface of Au/Nafion electrode with Na2SO3 as reductant. Compared the Pt/Nafion electrodes activity with Au/Nafion electrodes activity of the electro- chemical hydrogenation reaction in the water-benzene system, the results showed that the main products of benzene hydrogenation on the cathode are cyclohexene and cyclohexane, meanwhile, more cyclohexane is generated under the high cathode electric; the total current efficiency of benzene hydrogenation reaction on the Au/Nafion elec- trodes is up to 40% -90% （ - 1.6 - -0. 4V vs SCE） and the side reaction of hydrogen evolution have been well constrained in the cathode.