Self-assembled ZnIn2S4/SnS2 QDs S-scheme heterojunction for boosted photocatalytic hydrogen evolution: Energy band engineering and mechanism

Rapid and efficient transfer and separation of photo-induced carriers are critical for designing en-vironmentally friendly and efficient photocatalysts in catalytic hydrogen evolution. Here, we design a 0D/2D S-scheme heterojunction involving ZnIn2S4 (ZIS) nanosheets self-assembled with SnS2 quantum dots (QDs). The formation of the S-scheme ZIS/SnS2 QDs heterojunction is demonstrated by experimental character-istics and density functional theory (DFT) analyzes, which greatly promotes charge transfer and transport under the interfacial electric field (IEF), lengthens carrier lifetime, enhances light-harvesting properties, and significantly decreases the Gibbs free energy during the catalysis reaction. Therefore, the optimized ZIS/SnS2 photocatalyst achieves a high hydrogen production rate of 1.13 mmol g-1h-1, which is 16.14 folds the one of pure ZIS. This study provides novel perspectives into the reasonable design of S-scheme photocatalyst by virtue of the theories of energy band engineering and IEF adjustment. & COPY; 2023 Elsevier B.V. All rights reserved.