One-Step Synthesis and Gd3+ Decoration of BiOBr Microspheres Consisting of Nanosheets Toward Improving Photocatalytic Reduction of CO2 into Hydrocarbon Fuel

Abstract Rising carbon dioxide (CO2) levels in the atmospheric environment is a key cause of global warming. To reduce the concentration of CO2 in the atmosphere, converting CO2 into hydrocarbon fuels is an eye-catching strategy. Herein, we achieve in-situ doping of Gd3+ for BiOBr microspheres consisting of nanosheets via a simple hydrothermal method. The resulting Gd doped BiOBr structure (BiOBr/Gd) exhibits considerable improvement on photocatalytic activities for CO2 reduction. Compared to bare BiOBr (24.097 μmol g-1 for 3 h), the BiOBr/Gd-0.05 displays excellent performance of CO2 photoreduction with nearly five-fold increase in the rate of methanol emission (123.711 μmol g-1 for 3 h). The enhanced CO2 reduction activities of BiOBr/Gd-0.05 are attributed to the mechanism that Gd3+ ions are introduced into the lattice of BiOBr to broaden the visible light response. Furthermore, we discuss the mechanism of photocatalytic CO2 reduction, where holes are the main active species in the process of CO2 reduction.