Ag@AgBr/GO/Ni等离子体光阴极膜电极的电荷转移机制和光电催化活性

Charge transfer mechanism and photoelectrocatalytic activity of Ag@AgBr/GO/Ni plasma photocathode film electrode

采用电化学共沉积法制备了含少量氧化石墨烯(GO)的Ag@AgBr/GO/Ni表面等离子体膜电极,该膜电极的表面微观形貌呈现出GO覆盖在AgBr颗粒表面的褶皱结构。纳米Ag分布在AgBr表面以及GO和AgBr接触的边缘,尺寸分布从10 nm到120 nm基本上呈正态分布趋势,颗粒尺寸多为50~80 nm。作为光阴极Ag@AgBr/GO/Ni膜电极表现出优异的催化活性和循环稳定性,光电化学过程与暗态的电化学过程的本质不同在于其存在光生电子由价带跃迁至导带而产生的光电流。在可见光照射和最佳阴极偏压下,良好的光电协同效应、GO优异的导电性能和较大颗粒纳米Ag增强的表面等离子体效应是Ag@AgBr/GO/Ni优异光电催化性能的主要原因。

Ag@AgBr/graphene oxide(GO)/Ni surface plasma film electrode containing a small amount of GO was prepared by electrochemical co-deposition method.The surface morphology of the film electrode shows the corrugated structure of GO covers on the surface of AgBr particles.Ag nanoparticles are distributed on the surface of AgBr and near the contact edge between the GO and AgBr.The size distribution of Ag nanoparticles ranges from 10 nm to 120 nm,showing a normal distribution trend,and the particle size is mostly 50-80 nm.Ag@AgBr/GO/Ni film electrode as photocathode has excellent photoelectrocatalytic(PEC)activity and cycle stability.A major difference between the photoelectrochemical reaction under visible light irradiation and the dark electrochemical reaction arose from photocurrent produced by the transition of a photogenerated electron from the valence band to the conduction band.Under visible light irradiation and optimum cathode bias,the good photoelectric synergistic effect,the excellent electroconductivity of GO and the enhanced surface plasmon effect of large Ag nanoparticles are the main reasons for the excellent PEC performance of Ag@AgBr/GO/Ni film electrode.