In this paper, preparation and activity of porphyrin-modified TiO2 nanocrystals (PP/modified TiO2) with different non-metal content was investigated for visible light induced photocatalytic applications. The degradation of methyl orange has been considered in this regard. The characterization was carried out using XRD, BET, DRS, and UV–Vis techniques. Results revealed that modified TiO2 nanocrystals possess only the anatase phase with crystal sizes of about 39–15 nm and high surface areas of 2.8–37.3 m2/g. The amount of non-metal doping affects the activity of modified TiO2 nanocrystals remarkably. The 5 mol% non-metal doping exhibited enhancing photocatalytic activity in this work. It was found that presence of porphyrin and nonmetal ions cause a shift in the energy band gap to significantly lower levels (from 3.4 to 2.2 eV). Results of the degradation of methyl orange revealed that modified TiO2 nanocrystals provide more than 87% degradation under visible light which makes the applicability of TiO2 photocatalysts even more versatile.
