Synthesis of mesoporous TiO2-coupled Fe2O3 as efficient visible nano-photocatalysts for degrading colorless pollutants

In this paper, a feasible route is developed to greatly enhance the visible photocatalytic activities of α-Fe2O3 nanoparticles for degrading colorless pollutants by coupling a suitable amount of mesoporous nanocrystalline anatase TiO2. Based on the atmosphere-controlled steady-state surface photovoltage spectra, transient-state surface photovoltage responses, photoelectrochemical measurements and O2 temperature-programmed desorption, it is suggested that the coupled TiO2 with a high-level conduction band bottom would act as a high-level platform, could facilitate the uncommon spatial transfers of visible-excited energetic electrons from Fe2O3 to TiO2, and the mesoporous structure of TiO2 could promote the capture of the energetic electrons by O2 by enhancing the O2 adsorption. This is favorable to prolong the carrier lifetime and to promote the charge separation, leading to the obviously-enhanced visible photoactivities. The developed strategy would provide us with a simple and feasible idea to greatly improve the photocatalytic performance of visible-response oxide-based nano-semiconductors.