Photocatalytic activity and microstructure of micro-arc oxidized TiO₂:Cr³⁺ composite coatings

Abstract

In this study, the TiO2:Cr3+ composite coatings were formed in phosphate-based electrolyte with the addition of Cr2O3 by micro-arc oxidation (MAO) treatment. The chemical and physical properties of coatings were investigated. The results showed that the TiO2:Cr3+ coatings are mainly composed of Ti, O, P and Cr. And the Cr content in the coatings increased with the MAO treatment time. XRD results showed the TiO2:Cr3+ coatings are composed of anatase phase and anatase content varied with the treatment time. XPS results indicated that Ti2p spin-orbit components of the TiO2:Cr3+ coatings are shifted towards higher binding energy, compared with the pure TiO2 coating, suggesting that some of the Cr3+ ions are incorporated into TiO2 lattice. The photocatalytic experiment results showed that the TiO2:Cr3+ coatings are of higher photocatalytic activity than that of the pure TiO2 coatings. Besides, the Cr3+ is of positive effect on photocatalytic properties of TiO2:Cr3+ coatings.