Enhanced visible light photocatalytic activity of P-block elements (C, N and F) doped porous TiO 2 coatings on Cp-Ti by micro-arc oxidation

P-block elements (C, N and F) doped porous TiO 2 coatings were developed on commercially pure titanium by micro-arc oxidation (MAO) for visible light photocatalytic activity. Porous structured photocatalytic system has been developed with the use of different electrolytes. The geometry of porous coatings was analyzed by optical profilometer and their results confirmed that the surface roughness, width and depth of pores vary with respect to the doped elements. The anatase and rutile phase percentage in the pure and doped TiO 2 coatings was estimated by their XRD patterns. EDS analysis confirms the presence of C, N and F (2.2, 3.1 and 3.8 at.%) doped elements in the TiO 2 coatings. The band gap energies of C, N and F doped TiO 2 coatings were significantly reduced into 3.03, 3.04 and 3.02 eV, respectively than pure TiO 2 (3.15 eV) coating. The photoluminescence study indicates the formation of additional electronic states by the influence of C, N and F doped elements in TiO 2 . This resulted in the reduced rate of recombination of photogenerated electron–hole pairs. The photocatalytic activity of MAO produced pure and doped TiO 2 coatings have been investigated with methylene blue dye as a target pollutant. The results confirmed that the doped TiO 2 showed higher rate of dye degradation than pure TiO 2 . In particular F doped TiO 2 revealed higher photocatalytic activity among all other doped TiO 2 .