The Rutile Phase of TiO2/Graphene Films: Sol–Gel Method, Phase Transition, Photocatalytic Properties

Abstract

TiO2 materials are of great interest in different applications because of the controllable preparation of different structures. In this paper, the TiO2 and TiO2/graphene films with different phase structure and inserted graphene layer between Cu substrate and TiO2 film were prepared by sol–gel method at different annealing temperatures, and then used as catalysts for photo-degradation of methylene blue (MB) dye solution under ultraviolet irradiation using 15 W of ultraviolet lamp. The effects of annealing temperature and graphene layer on the phase structure, morphology, chemical composition, binding energy level, and photocatalytic performance of TiO2 films were studied in details. XRD results reveal that the anatase phase of TiO2 films transfers to rutile phase with the increase in annealing temperature, and the introducing of graphene film layer can accelerate the phase transformation of anatase to rutile and improve the crystallization quality of TiO2 films. It is found that the MB degradation efficiency of TiO2 and TiO2/graphene films is enhanced with the increasing annealed temperature, which shows that the existence of rutile phase, well crystalline quality and the better dispersion of the TiO2 particles are helpful in photocatalytic behavior. In addition, compared to the rutile phase TiO2 film, the rutile phase TiO2/graphene films at annealed temperatures of 900 °C exhibit much higher photocatalytic activity due to the introduction of graphene films.