Facile preparation of immobilised visible light active W–TiO2/rGO composite photocatalyst by plasma electrolytic oxidation process

A highly efficient immobilised W–TiO2/rGO composite photocatalyst was prepared as a coating on titanium using plasma electrolytic oxidation (PEO) with particle addition. The high dopant concentration in TiO2 resulted in smaller crystallite size, increased lattice strain, and dislocation density. The optimum W containing G6W sample has improved electron mobility, higher charge carrier separation efficiency, and lower electron-hole recombination rate. This can be ascribed to the number of different defect centres emerging from tungsten interstitials and higher oxygen vacancies in the TiO2 structure. The catalyst exhibited enhanced photocatalytic degradation efficiency (93%) of methylene blue dye than the pure TiO2, which was attributed to the synergetic effect of 2-D structured rGO and the changes incorporated upon tungsten interstitials in the TiO2. The present research concludes that W–TiO2/rGO photocatalyst by PEO process can be a good candidate for efficient, low cost, reusable, and visible-light-driven immobilised photocatalyst for textile wastewater treatment.