Photocatalytic decomposition of methylene blue by Cr/TiO₂ composite coatings

ABSTRACT

In this research, the Cr/TiO₂ composite coatings were formed in Na₂HPO₄+ NaOH + Cr₂O₃ by micro-arc oxidation (MAO) technology with different ratios of anodic and cathodic currents. Surface morphology results showed that the pancake-like structures on the coating surface decreased with the ratio decreased. XRD results showed the TiO₂:Cr³⁺ coatings are composed of anatase and rutile phase and the anatase content first increased and then decreased. XPS results indicated that Ti2p spin–orbit components of the Cr/TiO₂ composite 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 photocatalytic activity of Cr/TiO₂ MAO coatings can be greatly enhanced with a moderate amount of Cr³⁺.

KEYWORDS:

• MAO
• Ratio
• Currents‌
• TiO₂
• Cr/TiO₂
• Photocatalytic

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The financial aids are from Research on The Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant 19KJB430024) and The Natural Science Foundation of Jiangsu Province (Grant BK20181036).