Photocatalytic H₂O₂ production from O₂ and H₂O is an economical and environmentally sustainable approach. However, the reliance on sacrificial agents and pure O₂ greatly limits the practical application of numerous photocatalysts. Herein, a novel S-scheme photocatalyst composed of MgIn₂S₄ and covalent organic framework (COF) was developed toward efficient photocatalytic H₂O₂ evolution under pure water and air. MgIn₂S₄/COF (MC) S-scheme heterojunction was constructed by decorating MgIn₂S₄ nanosheets on hollow spherical COF using wet chemistry. The H₂O₂ yield of the optimal MC composite in pure water and air was 4.52 mmol⸱g⁻¹⸱h⁻¹ under pure water and air, which was separately 6.6 times and 9.4 times higher than that of pristine MgIn₂S₄ and COF. Photocatalytic mechanism characterizations confirmed that the continuous 2e⁻ O₂ reduction and 4e⁻ H₂O oxidation simultaneously occurred within this reaction system, and both ·O₂^– and e^– were pivotal intermediates for H₂O₂ evolution. The MC S-scheme heterojunction was advantageous to the effective separation and transfer of photogenerated electrons and holes, thereby enhancing the photocatalytic H₂O₂ production activity. This work offers important guidance for constructing high-efficiency COFs-based S-scheme heterojunction for H₂O₂ production.

中文翻译：

---

MgIn2S4/COF S-Scheme 异质结构改善纯水和空气下光催化 H2O2 的产生


从 O₂ 和 H₂O 光催化生产 H₂O₂ 是一种经济且环境可持续的方法。然而，对牺牲剂和纯 O₂ 的依赖极大地限制了众多光催化剂的实际应用。在此，开发了一种由 MgIn₂S₄ 和共价有机框架 （COF） 组成的新型 S 型光催化剂，用于在纯水和空气下高效光催化 H₂O₂ 析出。通过使用湿化学将 MgIn₂S₄ 纳米片装饰在空心球形 COF 上，构建了 MgIn₂S₄/COF （MC） S 型异质结。最佳 MC 复合材料在纯水和空气中的 H₂O₂ 产率为 4.52 mmol⸱g⁻¹⸱h⁻¹，分别比原始 MgIn₂S₄ 和 COF 高 6.6 倍和 9.4 倍。光催化机理表征证实，连续的 2e⁻ O₂ 还原和 4e⁻ H₂O 氧化同时发生在该反应体系内，并且两者 ·O₂^– 和 e^– 是 H₂O₂ 进化的关键中间体。MC S 型异质结有利于光生电子和空穴的有效分离和转移，从而提高光催化 H₂O₂ 的产生活性。这项工作为构建基于 COF 的高效 H₂O₂ 生产 S 型异质结提供了重要指导。