Surface Dual Metal Occupations in Fe-Doped Fe x Bi2-x O3 Induce Highly Efficient Photocatalytic CO2 Reduction

CO2 possesses extraordinary thermodynamicstability,and its reduction reaction involves multiple electron-transfer processes.Thus, high-density electron occupation on a catalyst surface is aneffective driving force for improving the photocatalytic activity.Here, we report on the fabrication of Fe-doped Bi2O3 catalysts (denoted as Fe x Bi2-x O3) with different Fecontents using the solvothermal method. The self-assembled catalysthas a nanoflower-like morphology, and its performance of CO2 reduction to CO is improved largely dependent on the Fe content.In the sample with a 7.0% Fe content (Fe0.07Bi1.93O3), the CO evolution rate reaches 30.06 mu mol g(-1) h(-1), which is about 6 times higherthan the 4.95 mu mol g(-1) h(-1) of pristine Bi2O3, and shows excellent photostabilityafter three cycles, with each cycle lasting for 7 h. Theoretical calculationand spectral characterization reveal that such a good CO2 reduction reaction performance arises from effective surface occupationof Fe, which not only enhances sunlight absorption but also significantlyincreases the surface electron density on the double metal activesites. This work provides a new strategy for improving the photocatalyticperformance by surface metal doping in some metal oxide photocatalysts.