Optimization of Electrolyte Composition for Enhanced Photocatalytic Performance of the Ceramic Coating Produced on Brass by Plasma Electrolytic Oxidation

Abstract

PEO coatings are formed by subjecting a metal substrate to an electrolytic plasma discharge, resulting in the formation of a porous and rough oxide layer. Herein, the significant role of the chemical composition of the electrolyte system and additives in the formation of an oxide coating on brass alloy in the PEO process was investigated. It was observed that the coating created with 8 g/l aluminate, 1 g/l NaOH, and 1 g/l KF electrolyte had higher homogeneity than other coatings. This is because a composite oxide coating of Cu2O, ZnO, and AlCuO2 was formed. Methylene Blue (MB), a widely used dye in various industries, is known to be persistent and environmentally harmful. The photocatalytic activity of the PEO coating on brass for the removal of MB was investigated under visible light exposure. According to the results, the presence of the sample produced in an electrolyte containing 8 g/l Aluminate, 1 g/l NaOH, and 1 g/l KF resulted in a degradation rate of approximately 65% for MB photodegradation after 6 h of irradiation. The PEO-coated brass shows promising photocatalytic efficiency compared to our research group's PEO-coated TiO2 coatings, indicating its potential as a photocatalyst. The results highlight that PEO coating on brass could be a potential candidate for photocatalytic and photoelectrochemical applications.