C, N co-doped TiO 2 /TiC 0.7 N 0.3 composite coatings prepared from TiC 0.7 N 0.3 powder using ball milling followed by oxidation

Abstract Ball milling followed by heat oxidation was used to prepared C, N co-doped TiO 2 coatings on the surfaces of Al 2 O 3 balls from TiC 0.7 N 0.3 powder. The as-prepared coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectrophotometer (UV–vis). The results show that continuous TiC 0.7 N 0.3 coatings were formed after ball milling. C, N co-doped TiO 2 /TiC 0.7 N 0.3 composite coatings were prepared after the direct oxidization of TiC 0.7 N 0.3 coatings in the atmosphere. However, TiO 2 was hardly formed in the surface layer of TiC 0.7 N 0.3 coatings within a depth less than 10 nm during the heat oxidation of TiC 0.7 N 0.3 coatings in carbon powder. Meanwhile, the photocatalytic activity evaluation of these coatings was conducted under the irradiation of UV and visible light. All the coatings showed photocatalytic activity in the degradation of MB no matter under the irradiation of UV or visible light. The C, N co-doped TiO 2 /TiC 0.7 N 0.3 composite coatings showed the most excellent performance. The enhancement under visible light irradiation should attribute to the co-doping of carbon and nitrogen, which enhances the absorption of visible light. The improvement of photocatalytic activity under UV irradiation should attribute to the synergistic effect of C, N co-doping, the formation of rutile-anatase mixed phases and the TiO 2 /TiC 0.7 N 0.3 composite microstructure.