Photocatalytic CO₂ reduction has attracted extensive attention because of its abilities to generate renewable clean fuels while immobilizing CO₂. However, the widely used CO₂ reduction photocatalysts generally have the problems of inadequate light absorption performance and insufficient photocatalytic reaction yield. Here we report 0D/2D CsPbBr₃ quantum dot/CuCo₂O₄ nanosheet composites (CsPbBr₃ QD/CuCo₂O₄ NS composites) synthesized by mechanical mixing method, which are applied for photocatalytic CO₂ reduction. Thanks to the narrow bandgaps of CsPbBr₃ QD and CuCo₂O₄ NS, CsPbBr₃ QD/CuCo₂O₄ NS composites represent strong light absorption performance. The p-n heterojunction forms between CsPbBr₃ QD and CuCo₂O₄ NS obviously boosts the charge separation, leading to the photocatalytic activity and stability of CsPbBr₃ QD/CuCo₂O₄ NS composites significantly exceeding that of CsPbBr₃ QD and CuCo₂O₄ NS. After 5 hours of photocatalytic reaction, the generation rate for CH₄ of CsPbBr₃ QD/CuCo₂O₄ NS composites is 285.93 μmolg^-1, which is about 3.2 times and 9.2 times higher than CsPbBr₃ QD (88.08 μmolg^-1) and CuCo₂O₄ NS (30.92 μmolg^-1), respectively. This work provides a new insight to construct novel heterojunction photocatalysts based on lead halide perovskite QD, which shows the enhanced photocatalytic activity and light absorption performance.

光催化CO _{2还原因其在固定CO 2}的同时产生可再生清洁燃料的能力而受到广泛关注。然而，目前广泛使用的CO ₂还原光催化剂普遍存在光吸收性能不足和光催化反应收率不足的问题。在这里，我们报道了通过机械混合法合成的0D/2D CsPbBr ₃量子点/CuCo ₂ O ₄纳米片复合材料（CsPbBr ₃ QD/CuCo ₂ O ₄ NS 复合材料），用于光催化CO ₂还原。由于 CsPbBr _{3的窄带隙}QD和CuCo ₂ O ₄ NS、CsPbBr ₃ QD/CuCo ₂ O ₄ NS复合材料表现出很强的光吸收性能。_{CsPbBr 3} QD和CuCo ₂ O ₄ NS之间形成的pn异质结明显促进了电荷分离，导致CsPbBr ₃ QD/CuCo ₂ O ₄ NS复合材料的光催化活性和稳定性明显超过CsPbBr ₃ QD和CuCo ₂ O ₄ NS。光催化反应5 小时后，CsPbBr _{3对CH 4的生成速率}QD/CuCo ₂ O ₄ NS 复合材料为285.93 μmolg ^{-1 ，分别是CsPbBr} ₃ QD（88.08 μmolg ^-1）和CuCo ₂ O ₄ NS（30.92 μmolg ^-1 ）的3.2倍和9.2倍。这项工作为构建基于卤化铅钙钛矿量子点的新型异质结光催化剂提供了新的视角，显示出增强的光催化活性和光吸收性能。