T Arunnellaiappan

Solar photocatalytic activity of nitrogen doped TiO2 coating by micro-arc oxidation

ABSTRACT Nitrogen doped porous TiO2 (N-TiO2) coating was developed from titanium nitride (TiN) by micro-arc oxidation (MAO), whereas TiN was prepared by plasma nitriding on commercially pure (Cp) titanium. The surface roughness of the N-TiO2 coating was greater than that of the TiO2 coating due to different MAO processing parameters. The band gap energy of N-TiO2 coating was reduced to 2.92 eV compared to TiO2 coating. The band gap energy reduction of N-TiO2 was attributed to nitrogen doping and the mixture of anatase, rutile and new phase (TiN0.30). The photoluminescence study demonstrated that the recombination rate of photo-generated electron–hole pairs of TiO2 was significantly suppressed after doping with nitrogen. N-TiO2 exhibited higher photocatalytic activity towards methylene blue dye degradation than to pure TiO2 coating. The recyclability test of N-TiO2 coating showed constant photocatalytic efficiency after the fourth run. Hence, N-TiO2 porous coating could be a promising material for immobilised solar photocatalytic applications.