Restructuring surface frustrated Lewis acid-base pairs of BiOBr through isomorphous Sn doping for boosting photocatalytic CO2 reduction

Photocatalytic conversion of CO2 into valued chemicals has evoked broad interest. However, the photocatalytic efficiency is limited by the adsorption and activation capability of the catalyst surface for CO2. Here, isomorphically Sn (IV) doped BiOBr is achieved through a facile chemical method. The as-prepared Sn-doped BiOBr demonstrates the enhanced performance of photocatalytic CO2 reduction into CO. Thereinto, the 4Sn-BiOBr sample shows the best activity with the CO yield of 165.6 μmol·g−1·h−1, which is 7.8 times higher than that of pristine BiOBr. Sn ions and oxygen vacancies (OVs) are shown to be simultaneously introduced into the crystal lattice of BiOBr. As a result, surface frustrated Lewis acidic sites and Lewis basic sites of BiOBr are constructed and the activation capability for CO2 is improved obviously. This work presents the feasible tunability of catalytic active sites for catalyst at atom-scale, and offers fundamental insights for understanding of the mechanism of photocatalytic CO2 reduction.