Fast Interlayer Charge Separation and Transmission in ZnIn 2 S 4 /CNTs/ZnS Heterojunctions for Efficient Photocatalytic Hydrogen Evolution

The construction of close contact heterojunction structures is crucial to modify photocatalytic performance. Here a series of heterojunction ZnIn2S4/CNTs/ZnS nanocomposites for photocatalytic hydrogen evolution were synthesized by a simple thermal reflux approach. The ideal ZnIn2S4/CNTs/ZnS sample has a photocatalytic hydrogen evolution rate of 0.9363 mmol ⋅ g−1 ⋅ h−1 with favorable cycle stability, which is about 16.9 and 5.5 times that of pure ZnIn2S4 and binary ZnIn2S4/ZnS. The tight interfacial contact between ZnIn2S4, ZnS, and CNTs raises photogenerated charge carrier separation efficiency. CNTs have a high electrical conductivity, which allows them to receive and transport photogenerated electrons effectively. Therefore, the recombination of photon-generated charges may be efficaciously restrained, and the accepted electrons can be rapidly transported to reactive sites for production of hydrogen. Simultaneously, density functional theory (DFT) simulations show that introducing CNTs can enhance electronic characteristics and add additional charge carriers. This study shows that well-designed CNTs-based heterojunction structure can effectively promote charge separation in photocatalysis.