Study on photocatalytic activity of plasma electrolytic oxidised doped TiO2 coating

Severe dye contamination makes titanium dioxide (TiO2) coating a key photocatalytic material, hence enhancing its catalytic activity is research priority. Copper (Cu)/titanium dioxide composite coatings were fabricated via plasma electrolytic oxidation (PEO) using electrolytes containing trisodium phosphate (Na3PO4) (concentration: 2–10 g/L, 2 g/L stepwise), sodium fluoride and copper oxide. Microstructure, crystalline phase and photocatalytic activity were fully characterised. Higher phosphate concentration reduces surface micropore density; energy-dispersive spectroscopy proves homogeneous dispersion of oxygen, sodium, fluoride and copper. X-ray diffraction confirms coexisting anatase and rutile, and anatase content rises first then declines. X-ray photoelectron spectroscopy peak shift verifies successful Cu3+ doping into titanium dioxide lattice. The coating derived from 6 g/L trisodium phosphate delivers optimal performance with 61.9% decolourisation after 200 min irradiation. Copper doping optimises electronic structure and charge separation, enabling better degradation than pristine titanium dioxide.