Reconstruction of surface oxygen vacancy for boosting CO2 photoreduction mediated by BiOBr/CdS heterojunction

Construction of catalytic active sites is effective strategy to boost the photocatalytic property of CO2 reduction by solar energy. In this paper, BiOBr/CdS heterojunctions with surface oxygen vacancies were prepared by a one-pot hydrothermal method. The experimental results show that the productive velocities of CO and CH4 for CO2 photoreduction over optimal BiOBr/CdS heterojunction are 115.3 μmol g-1h−1 and 12.7 μmol g-1h−1, being 15.3 and 18.2 times as high as those of the pristine CdS, or 4.7 and 7.0 times as big as those of pure BiOBr separately. It is found that the heterojunction structure of BiOBr/CdS could promote the separation and transfer of photogenerated carriers, and improve the light stability of catalyst. The more enriched oxygen vacancies for BiOBr in BiOBr/CdS with enhanced electron density are considered as active sites for the adsorption and activation of CO2 exhibiting lewis acid feature to boost the efficiency of CO2 photoreduction. This work illuminates novel information and viewpoints into the construction of heterojunction catalyst with vacancy for photocatalytic CO2 reduction.