Mixed-phase TiO2 photocatalysis: correlation between phase composition and photodecomposition of water pollutants

In most cases, the combination of both anatase (up to 80%) and rutile (up to 20%) structures in a mixedphase TiO2 semiconductor results in a better photocatalytic performance compared to the pure phase. The improvement from anatase to rutile is brought about by the enhanced transportation of photogenerated electrons. This consequently results in improved efficiency of the photoelectric and photocurrent conversion. This review highlights the effects of the morphology, particle size, and crystal structure of mixed-phase TiO2 toward the photodegradation of water pollutants. It was demonstrated that the synergistic effect between anatase and rutile TiO2 due to the interfacial electron transfer from rutile to anatase improved the photocurrent as well as the overall conversion efficiency of the anatase photoanodes. The morphologies of mixed-phase TiO2 also contributed to the final photodegradation properties. The charge and electron transfer of mixed-phase TiO2 improved the 1D structure. This consequently enables photodegradation at the visible light range.