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

In this study, alpha-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 O-2 by means of the atmosphere-controlled surface photovoltage spectra, along with the photoelectrochemical I-V curves. On the basis of the O-2 temperature-programmed desorption measurements, it is suggested for the first time that the promotion effect results from the increase in the amount of O-2 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.