Studying the role of dual vacancies over g-C3N4/Zn0.3Cd0.7S for photocatalytic CO2 reduction

Defect engineering as an important surface regulation method, is closely related to the adsorption, activation and transformation of reactant molecules. To improve the efficiency of photocatalytic CO2 reduction from the interfacial perspective, g-C3N4/Zn0.3Cd0.7S (CN/ZCS) heterojunction with dual vacancies were successfully synthesized. The production of CO for the optimal sample (3% CN/ZCS) is significantly improved, about 3.5 times of ZCS and 309.8 times of CN, respectively. Meanwhile, the CO2 adsorption and transformation process are deduced and revealed by monitoring the intermediate and final products on the in-situ FTIR. The underlying enhanced reason can be elucidated by the defective sites and Z-scheme transfer model, which increase the carrier density, active sites and the utilization of photogenerated charge carriers (PCCs). This study provides a new and powerful example in designing novel heterojunction photocatalysts by defect engineering, and helps us to enhance the photocatalytic activity from the interfacial perspective.