Interfacial intimacy and internal electric field modulated S-scheme Sv-ZnS/ZnIn2S4 photocatalyst for efficient H2 evolution and CO2 reduction

The construction of S-scheme heterojunctions is an effective approach to realize artificial photocatalytic processes. For the higher solar energy conversion efficiency, current research focuses on improving the interfacial intimacy and precisely modulating the strength of the internal electric field (IEF). To address this issue, we propose a novel MOF-based synthesis and derivation strategy. The heterojunction obtained by this strategy tends to form an intimate interface and a tunable IEF, which facilitates the transfer and separation of photogenerated carriers. Herein, a ZnS/ZnIn2S4 (ZIS) S-Scheme heterojunction containing sulfur vacancies (Sv) was successfully synthesized, and its good photocatalytic hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR) activity confirmed the feasibility of this strategy. The prepared Sv-ZnS/ZIS exhibits an apparent quantum yield of 19.8 ± 1.0 % at 420 nm and a hydrogen evolution rate of 2912.3 ± 185.9 μmol g-1h-1, which is 9.0 and 33.6 times higher than pure ZIS and Sv-ZnS, respectively. Furthermore, the yield of photoreduction CO2 to CO reaches 2075.7 ± 63.0 μmol g-1h-1 with a CO selectivity of 93.0 ± 0.8 %. This work provides new sights for the rational design and construction of S-scheme photocatalysts with sulfur vacancies for efficient photocatalysis.