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

• Published in: Applied catalysis. A, General General, 2023-01, Vol.650, p.118975, Article 118975
• Main Authors: Chi, Yuhua, Chen, Zhengnan, Ma, Hao, Yuan, Saifei, Hao, Chunlian, Ren, Hao, Zhao, Wen, Zhu, Houyu, Ling, Cuicui, Guo, Wenyue
• Format: Article
• Language: English
• Subjects: Active site; DFT; MoSi2N4; Photocatalytic performance; Point defect
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2022.118975

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. [Display omitted] •Defect structures of MoSi2N4 show a red shift in light absorption.•Calculated Gibbs free energies reveal the suitability for CO2 reduction.•The type of active site can regulate the selectivity of the reduction products.•The coordination environment of active sites has an important effect on the catalytic performance.