Photocatalytic CO₂ reduction technology has engaged significant attention due to its high efficiency, high selectivity, and environmental friendliness. However, its application is severely restrained by issues such as low separation efficiency of photogenerated carriers and a limited light absorption range. This work proposes an innovative MgCr₂O₄/MgIn₂S₄ magnesium-based spinel/spinel heterostructure photocatalyst to improve the photocatalytic CO₂ reduction efficiency through the synergistic contributions of S-scheme heterojunction and photothermal effect. On the one hand, the unique S-scheme charge transfer mechanism enables the effective separation of photogenerated carriers. On the other hand, the photothermal effect allows an accelerated charge migration by increasing the reaction center temperature. Moreover, the abundant oxygen vacancies serve as electron traps and CO₂ adsorption sites, unifying reaction and adsorption sites and substantially improving catalytic efficiency. Under UV–vis and UV–vis-NIR illumination, the average CO yields of the MgCr₂O₄/MgIn₂S₄ composite are 8.03 and 15.62 μmol g^–1 h^–1, respectively, greatly higher than those of pure MgCr₂O₄ and MgIn₂S₄ samples. Furthermore, the fabricated photocatalyst demonstrates excellent performance and structure stability. Therefore, this work may offer a new strategy for designing efficient and stable photocatalysts.

中文翻译：

---

MgCr2O4/MgIn2S4 尖晶石/尖晶石 S 型异质结：一种用于光热辅助光催化 CO2 还原的稳健催化剂


光催化 CO₂ 还原技术因其高效、高选择性和环境友好性而受到广泛关注。然而，其应用受到光生载流子分离效率低和光吸收范围有限等问题的严重制约。本工作提出了一种创新的 MgCr₂O₄/MgIn₂S₄ 镁基尖晶石/尖晶石异质结构光催化剂，通过 S 型异质结和光热效应的协同作用提高光催化 CO₂ 还原效率。一方面，独特的 S 型电荷转移机制能够有效分离光生载流子。另一方面，光热效应通过提高反应中心温度来加速电荷迁移。此外，丰富的氧空位作为电子陷阱和 CO₂ 吸附位点，统一反应和吸附位点，大大提高了催化效率。在紫外-可见光和紫外-可见光照射下，MgCr₂O₄/MgIn₂S₄ 复合材料的平均 CO 产率分别为 8.03 μmol ^{g-1 h-1}，远高于纯 MgCr₂O₄ 和 MgIn₂S₄ 样品。此外，所制备的光催化剂表现出优异的性能和结构稳定性。因此，这项工作可能为设计高效稳定的光催化剂提供一种新的策略。