Effect of point defect-induced surface active sites of MoSi2N4 on performance of photocatalytic CO2 reduction

The selectivity of photocatalytic CO 2 reduction is often limited by the surface active sites of the catalyst. To overcome this limitation, the point defects are applied to the structural design of MoSi 2 N 4. Three different point defect structures (N Mo _Si, N Si _Si and N Abs _N) are screened out. The selectivity of photocatalytic products is closely related to the type of active sites, the N Abs _N with N active sites reduce CO 2 to CO, however, the N Mo _Si and N Si _Si with Si active sites reduce CO 2 to HCOOH. Furthermore, the coordination environment of active sites has an important effect on the catalytic performance. The N Mo _Si and N Si _Si with the same Si active sites have different photocatalytic capabilities. This study provides theoretical guidance for the catalysts design to improve product selectivity by controlling point defects.