Copper Oxides on Brasses of Different Phase Composition: Anode Formation and Photoelectrocatalytic Activity

Copper oxides combined with other materials, for example, zinc oxide, are considered promising materials for photocatalytic processes of organic impurities’ oxidation or photoelectrochemical water splitting. One of the methods for one-stage production of oxide structures of complex composition is the anodic oxidation of alloys. Evaluation of the photocatalytic or photoelectrochemical activity of the obtained materials is possible using photoelectrochemical parameters: the photocurrent or photopotential generated under illumination. The purpose of the work is to determine the effectiveness of the using of Cu(I) oxides anodically formed in alkaline solution on the Cu–Zn system alloys with zinc concentration of 34 to 50 at %, in the water photoelectrochemical decomposition. The elemental composition of the alloys was determined using energy-dispersive microanalysis. With increasing zinc concentration in the studied concentration range, the phase composition changes from α- to β-phase, which is confirmed by the X-ray diffractometry data. The change in the composition and structure of the alloy is reflected in the photoelectrochemical parameters of the anodic oxide films formed thereon. The most promising material for photoelectrocatalytic transformations is an oxide film anodically formed in 0.1 M KOH on the alloy with zinc concentration of 50 at % and β-phase structure. At a relatively low defect concentration, the highest photocurrent is recorded thereat at a rather high quantum efficiency.