Interfacial Mediation by Sn And S Vacancies of p‐SnS/n‐ZnIn2S4 for Enhancing Photocatalytic Hydrogen Evolution with New Scheme of Type‐I Heterojunction

Abstract The construction of interfacial electric field (IEF) in semiconductor heterojunction is of great significance in boosting photocatalytic hydrogen evolution through efficient separation of photogenerated charge‐carriers. However, the exploitation of IEF in type‐I heterojunction has not been proposed for designing photocatalysts. Herein, based on the density functional theory prediction, p ‐SnS with different work functions modulated by Sn‐vacancy are compounded with n ‐ZnIn 2 S 4 containing S‐vacancy to form type‐I heterojunction. The optimized SnS/ZnIn 2 S 4 photocatalyst without co‐catalysts exhibits an impressive hydrogen evolution rate of 22.75 mmol g −1 h −1 , 6.23 times of ZnIn 2 S 4 . Systematic investigations reveal that the interfacial Sn‐S bond acts as a transport channel that accelerates the interface charge‐carriers transfer under the promotion of IEF originating from the significant Fermi level difference. A large difference in the surface photovoltage signal of SnS/ZnIn 2 S 4 and ZnIn 2 S 4 is achieved from effective photogenerated charge‐carriers separation by IEF. The new p‐n type‐I scheme of SnS/ZnIn 2 S 4 induced by the interfacial mediation can separate the photogenerated charge‐carriers, and retain the highly reductive electrons of ZnIn 2 S 4 for hydrogen evolution, overcoming the disadvantage of reduction potential decline in the typical type‐I scheme. This study will afford a new theoretical basis for the achievement of high‐efficiency photocatalytic hydrogen evolution through interface modulation.