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

Abstract

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.