Efficient Charge Carriers Separation and Transfer Driven by Interface Electric Field in FeS₂@ZnIn₂S₄ Heterojunction Boost Hydrogen Evolution

Abstract

Photocatalytic H2 evolution technology is regarded as a promising and green route for the urgent requirement of efficient H2 production. At present, low efficiency is a major bottleneck that limits the practical application of photocatalytic H2 evolution. The construction of high-activity photocatalysts is highly crucial for achieving advanced hydrogen generation. Herein, a new S-scheme FeS2@ZnIn2S4 (FeS2@ZIS) heterostructure as the photocatalyst was developed for enhanced photocatalytic H2 evolution. Density function theory (DFT) calculation results strongly demonstrated that FeS2@ZIS generates a giant interface electric field (IEF), thus promoting the separation efficiency of photogenerated charge carriers for efficient visible-light-driven hydrogen evolution. At optimal conditions, the H2 production rate of the 8%FeS2@ZIS is 5.3 and 3.6 times higher than that of the pure FeS2 and ZIS, respectively. The experimental results further indicate that the close contact between FeS2 and ZIS promotes the formation of the S-scheme heterojunction, where the interfacial charge transfer achieves spatial separation of charge carriers. This further broadens the light absorption range of the FeS2@ZIS and improves the utilization rate of photogenerated charge carriers. This work thus offers new insights that the FeS2-based co-catalyst can enrich the research on S-scheme heterojunction photocatalysts and improve the transfer and separation efficiency of photogenerated carriers for photocatalytic hydrogen production.

Keywords

• FeS₂@ZnIn₂S₄
• S-scheme heterostructure
• interface electric field
• hydrogen evolution reaction
• photocatalysis