Hierarchical Co₃O₄@CdIn₂S₄ p–n heterojunction photocatalysts, composed of ultrathin CdIn₂S₄ nanosheets supported on Co₃O₄ nanocubes, have been assembled through a facile solvothermal method for efficient CO₂ reduction with visible light. The solution-processed surface growth strategy is advantageous to form an intimately coupled interface in situ for the Co₃O₄@CdIn₂S₄ hybrids with easily controllable compositions. Diverse physicochemical characterization experiments reveal that the Co₃O₄@CdIn₂S₄ heterostructures have more catalytically active sites, increased CO₂ adsorption, as well as hampered recombination and accelerated separation and mobility of photoexcited charge carriers. As a result, the Co₃O₄@CdIn₂S₄ p–n heterojunction photocatalysts display greatly improved activity compared to their nanosheet-assembled CdIn₂S₄ counterpart, affording an optimal CO generation rate of 53 μmol h⁻¹ (i.e., 5300 μmol h⁻¹ g⁻¹) and a high CO selectivity of 93.3%. Besides, the optimized Co₃O₄@CdIn₂S₄ photocatalyst has a high apparent quantum efficiency (AQE) of 1.87% under monochromatic light irradiation at 420 nm. Importantly, such metal sulfide composite photocatalysts also exhibit excellent stability against photocorrosion, due to the efficient hole transfer from CdIn₂S₄ to Co₃O₄. On the basis of the band structures and catalytic evaluation results, a possible CO₂ photoreduction mechanism is further proposed.

中文翻译：

---

制备分级Co3O4 @ CdIn2S4 p–n异质结光催化剂，以改善可见光下的CO2还原

分层的Co ₃ O ₄ @CdIn ₂ S ₄ p–n异质结光催化剂，由负载在Co ₃ O ₄纳米立方体上的超薄CdIn ₂ S ₄纳米片组成，已经通过一种容易的溶剂热方法进行了组装，以利用可见光有效地还原CO ₂。固溶处理的表面生长策略有利于原位形成Co ₃ O ₄ @CdIn ₂ S ₄的紧密耦合界面具有易于控制的成分的混合动力车。不同的理化特性实验表明，Co ₃ O ₄ @CdIn ₂ S ₄异质结构具有更多的催化活性位点，增加了CO _2的吸附，并阻碍了光激发电荷载体的重组和加速了分离和迁移。结果，与纳米片组装的CdIn ₂ S ₄对应物相比，Co ₃ O ₄ @CdIn ₂ S ₄ p–n异质结光催化剂显示出大大提高的活性，提供了最佳的CO生成速率为53μmolh ^-1（即5300μmolh ^-1 g ^-1）和93.3％的高CO选择性。此外，优化的Co ₃ O ₄ @CdIn ₂ S ₄光催化剂在420 nm单色光照射下具有1.87％的高表观量子效率（AQE）。重要的是，由于从CdIn ₂ S ₄到Co ₃ O ₄的有效空穴转移，这种金属硫化物复合光催化剂也表现出优异的抗光腐蚀稳定性。基于能带结构和催化评价结果，进一步提出了可能的CO _2光还原机理。