The influence of electrolyte on photocatalytic activity of PEO coatings with incorporated Ce-ZSM5 formed on aluminum

The preparation and characterization of oxide coatings made by plasma electrolytic oxidation (PEO) process on aluminum in two different electrolyte solutions of opposite pH values with addition of Ce-enriched ZSM-5 zeolite are investigated in this paper. The first selected electrolyte solution is highly acidic pH < 3, prepared with tungstosilicic acid (H 4 O 40 SiW 12 ), while the second one is made with sodium tungstate (Na 2 WO 4 ) creating highly alkaline PEO environment with pH > 12. Phase structure, chemical composition, morphology, photoluminescent properties, and photocatalytic activity of deposited oxide coatings are discussed. Properties of PEO coatings are analyzed against processing time revealing dynamics of PEO under defined conditions. Both sets of oxide coatings have similar chemical composition and morphology, but the photocatalytic activity is considerably higher for oxide coatings made in alkaline environment.