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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。
Electrochemical and electrical methods were used to study the preparation of Au electrode on Nafion membrane by impregnation-reduction technique. The effects of Au complex immersion time, concentration of reducing agent and reducing temperature on the performance of Au / Nafion electrode were investigated. The results show that the electrode prepared at longer impregnation time, lower concentration of reductant and higher reduction temperature has better activity. When Na2SO3 is used as reductant, Au / Nafion composite with uniform deposition of Au particles can be obtained electrode. The electrode activity of Pt / Nafion electrode prepared by impregnation-reduction technique and Au / Nafion electrode prepared by impregnation-reduction method was compared in the electrochemical hydrogenation of water-benzene system. The results showed that the main products of hydrogenation of benzene at the cathode were cyclohexene and cyclohexane, and cyclohexane was mainly generated at high cathodic overpotential. The total current of hydrogenation and reduction of benzene at the cathode was achieved by Au / Nafion electrode The efficiency is up to 40% ~ 90% (-1.6 ~ -0.4V vs SCE), and the hydrogen evolution side reaction is better inhibited on Au / Nafion electrode.