Preparation of visible-light-active carbon and nitrogen codoped titanium dioxide photocatalysts with the assistance of aniline

C–N-codoped titanium dioxide photocatalysts were prepared by a hydrolysis–polymerization–calcination method. Analysis of X-ray photoemission spectroscopy indicated carbon and nitrogen were effectively doped into TiO2 particles. Furthermore, it became apparent that most of the nitrogen dopants were likely present in the chemical environment of oxidized nitrogen, where the majority of carbon atoms formed a mixed layer of deposited active carbon and C–O bond species on the surface of the TiO2 particles. The results of the photodecomposition of methylene blue under visible-light irradiation suggest the photocatalytic activity of the C–N-codoped TiO2 was greatly improved when compared with that of the undoped TiO2 photocatalyst.