Enhanced photocatalytic activity of C, F-codoped TiO₂ loaded with AgCl

A protocol is reported for the development of a unique type of a co-doped TiO₂ with two kinds of non-metal atoms, carbon (C) and fluorine (F), as a visible-light active photocatalyst system. C, F-codoped TiO₂ nanoobjects with anatase phase were synthesized by calcination of a mixture of TiOF₂ and sulfuric-acid-treated melamine. The C, F co-doping resulted in a red-shift of the absorption edge to 510 nm from the 390-nm value obtained for a control TiO₂ photocatalyst. The C, F-codoped TiO₂ shows photocatalytic activity under visible light irradiation. Furthermore, the loading of AgCl into the parent co-doped TiO₂ enhanced its activity for degradation of methylene blue dye by about 3.5 times in the first hour irradiation. A brief mechanism responsible for the enhancement is proposed in terms of the transfer of holes from C, F-codoped TiO₂ to the AgCl phase.