The use of powder photocatalysts in visible light catalysis can be hindered by the build-up of nanoparticles and the challenges associated with their recovery. As a result, photocatalytic coatings emerge as promising options for the degradation of pollutants. In this research, a coating of TiO2/Bi2WO6 was developed on a titanium (Ti) base through the process of plasma electrolytic oxidation (PEO), with a hydrothermal treatment employed as a subsequent step. The results from the phase analysis indicate that the coatings consisted of anatase, rutile, Bi2WO6, and Bi6Ti3WO18 phases. The application of a post treatment can induce a needle-like structure on the surface of the coating. This contributes to broadening the light response to visible light and suppressing the recombination of generated electron-hole pairs through photoexcitation. The photocatalytic degradation of methylene blue, driven by visible light and facilitated by the hydrothermal post treatment PEO coating, can reach up to 75 %. The proposed photocatalytic mechanism is based on insights gained from the Mott–Schottky analysis, Tauc plot, and scavenging experiments. The outcomes indicate that this straightforward, eco-friendly, cost-effective, and sturdy procedure holds promise as a viable coating technique in the realm of water treatment.
