碱性介质中铜镍合金及铜电极的光电化学研究

A PHOTOELECTROCHEMICAL STUDY OF CUPRO-NICKEL AND COPPER ELECTRODES IN ALKALINE SOLUTIONS

用动电位伏安法和光电化学方法对铜镍合金(7％Ni+93％Cu)和铜电极在碱性介质中的电化学行为进行了研究。铜镍合金电极的阳极氧化膜呈p型光电响应,光电响应来自电极表面的Cu_2O膜,其厚度大于纯铜电极的Cu_2O膜。铜电极在碱性Na_2SO_4溶液中电位正向扫描时的光响应呈p型,点蚀电位以后光响应从p型转为n型。

The electrochemical behavior of both 7%Ni-93%Cu alloy electrode and pure Cu electrode in alkaline solutions was studied by cyclic voltammetry and photocurrent response method. The alloy electrode had a larger p-type photoresponse than that on the Cu electrode, which implied a thicker CU2O layer on the alloy electrode surface resulting from NiO. In 0.05mol/L Na2SO4 solution (pH=9.1), the Cu electrode showed a p-type photoresponse initially, which changed to n-type when pitting corrosion occured at potentials more possitive than the critical breakdown potential. The transition from p-type to n-type might be related to the doping of the Cu2O film by SO42- ions.