Enhanced photocatalytic reduction of CO2 on BiOBr under synergistic effect of Zn doping and induced oxygen vacancy generation

In this work, different BiOBr powders (without and with Zn doping) were prepared. Their specific properties and photocatalytic performance were studied. Zn doped BiOBr showed higher carrier transportation ability, beneficial to high performance photocatalysis. Further analysis and theoretical calculations unveiled that Zn doping resulted in more dispersive energy band structure with improved oxygen vacancy (OV) generation due to lattice distortion. OV acted as trap centers, playing dominant role in carrier transportation enhancement, which also synergized with more dispersive energy band due to Zn doping, improving carrier separation and transfer. Besides, Zn doping would further strengthen trapping effect under OV existence, stimulating synergistic enhancement to spatial charge separation and transfer with OV. With synergy of Zn doping and OV, Zn doped samples produced 1.75 times higher CH4 generation during gas-solid photocatalytic reduction of CO2 under visible light, testifying successful conducting of Zn doping improved photocatalytic capacity on BiOBr.