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