H2S Involved Photocatalytic System: A Novel Syngas Production Strategy by Boosting the Photoreduction of CO2 While Recovering Hydrogen from the Environmental Toxicant

Abstract Simultaneous treatment of CO 2 and H 2 S by photocatalytic technology is of great significance in mitigating the greenhouse effect and environmental hazards, while producing valuable solar fuels at the same time. In this study, well‐defined CdS/TiO 2 :Cu hollow spheres with highly dispersed heterointerfaces are successfully constructed for photoreduction of CO 2 in presence of in situ generated H 2 S. Benefiting from the consumption of photo‐generated holes ( h + ) and large production of protons by H 2 S decomposition, the generation rates of CO (781.3 µmol·g −1 ∙h −1 , accounting for 94.9 v/v% of CO 2 reduction products) and H 2 (5875.1 µmol·g −1 ∙h −1 ) increased significantly, which are 1.4 and 68.9 times higher than that of the system without H 2 S, respectively. Moreover, the remediation of photocorroded CdS by H 2 S prolonged the service life of the heterojunction, and maintained a CO generation rate of 96.8% after 4 cycles with or without H 2 S. Notably, as a potential syngas production strategy, by adjusting the initial concentration of Na 2 S, the ratio of CO and H 2 is controlled from 1.07 to 7.21 to fulfill the demands of different chemical synthesis. This strategy opens up a new horizon for the combination of energy photocatalysis and environmental photocatalysis, which has great research and application prospects.