Facile Synthesis of Surface-Modified Nanosized α-Fe₂O₃ as Efficient Visible Photocatalysts and Mechanism Insight

Abstract

In this study, α-Fe2O3 nanoparticles with high visible photocatalytic activity for degrading liquid-phase phenol and gas-phase acetaldehyde have been controllably synthesized by a simple one-pot water-organic two-phase separated hydrolysis-solvothermal (HST) method. Further, the visible photocatalytic activity is enhanced greatly after modification with a proper amount of phosphate. The enhanced activity is attributed to the increased charge separation by promoting photogenerated electrons captured by the adsorbed O2 by means of the atmosphere-controlled surface photovoltage spectra, along with the photoelectrochemical I–V curves. On the basis of the O2 temperature-programmed desorption measurements, it is suggested for the first time that the promotion effect results from the increase in the amount of O2 adsorbed on the surfaces of Fe2O3 by the partial substitution of −Fe–OH with −Fe–O–P–OH surface ends. Expectedly, the positive strategy would be also applicable to other visible-response nanosized oxides as efficient photocatalysts. This work will provide us with a feasible route to synthesize oxide-based nanomaterials with good photocatalytic performance.