Constructing S-scheme heterojunction between TiO₂ and other reduction semiconductors can effectively enhance the intrinsically low carrier separation efficiency and increase the reduction ability of single TiO₂ photocatalyst. In this work, a hydrothermally synthesized 2D CaIn₂S₄ nanosheets, possessing the merits of narrow bandgap and strong reduction ability, have been developed to construct S-scheme heterojunction with TiO₂ nanofiber. It is found that the 2D CaIn₂S₄ nanosheets can be in-situ assembled onto the surface of 1D TiO₂ nanofiber to form a 2D/1D CaIn₂S₄/TiO₂ S-scheme heterojunction, which then presents an extremely reinforced H₂-evolution rate (ca. 564.66 μmol·g^–1·h^–1), about 3- and 7-fold higher than that of the single TiO₂ and CaIn₂S₄, respectively. Finally, the in-situ XPS, DFT calculations, steady and transient-state spectrum results indicate that the formation of S-scheme heterojunctions between CaIn₂S₄ and TiO₂. This work may deliver a novel and insightful inspiration for the development of high-efficiency S-scheme heterojunction photocatalysts.

中文翻译：

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2D/1D CaIn2S4/TiO2 S型异质结：原位水热合成和增强光催化析氢


在 TiO₂ 和其他还原半导体之间构建 S 型异质结可以有效提高本征低载流子分离效率，提高单个 TiO₂ 光催化剂的还原能力。本工作开发了一种水热合成的二维 CaIn₂S₄ 纳米片，具有窄带隙和强还原能力的优点，用 TiO₂ 纳米纤维构建 S 型异质结。研究发现，2D CaIn₂S₄纳米片可以原位组装到1D TiO₂纳米纤维表面，形成2D/1D CaIn₂S₄/TiO₂ S异质结，然后呈现出极强的H₂析出速率（约564.66 μmol·g^–1·h^–1），比单个TiO₂和CaIn₂S₄高约3倍和7倍分别。最后，原位 XPS、DFT 计算、稳态和瞬态谱结果表明，CaIn₂S₄ 和 TiO₂ 之间形成了 S 型异质结。这项工作可能为高效 S 型异质结光催化剂的开发提供新颖而有见地的启发。