Coordination engineering of the interfacial chemical bond and sulfur vacancies modulated S-scheme charge transfer for efficient photocatalytic CO2 reduction

Surface charge localization and poor carrier separation efficiency limited the of photocatalytic CO2 reduction (PCR) activity. Creating heterojunctions between the interfacial layers was an important strategy used to enhance catalytic activity. Here, a core-shell structure S-scheme catalyst was constructed by growing of Bi2WO6 (BWO) nanospheres on the surface of Zn0.5Cd0.5 S(V S-ZCS) nanospheres with abundant sulfur defect, and which was coordinated by the interface bonding and the sulfur vacancies (V-S) for efficient PCR. Meanwhile, the surface potential was 91 mV, indicating the creation of strong interface electric field (IEF). As part of the strong synergy of the Bi-S bond, IEF and V S , the improved photocatalyst exhibited high CO evolution rate of 86.16 mu mol.g(-1) , which was about 9.23 fold of the pristine V S-ZCS. This was attributed to production of *COOH intermediates on the V S-ZCS/BWO surface that had been proved to be crucial for PCR generation CO. Besides, electrons quickly migrated through the formed Bi-S bonds to the catalytic sites, accelerating charge separation. The use of V S as electron traps was beneficial for regulating the localization of photogenerated charges on the surface of S-scheme heterostructure. The Bi-S bonds and V S modulated S-scheme charge transfer for efficient photocatalytic CO2 reduction provides new insights into photocatalytic CO2 reduction.