The introduction of oxygen vacancies (OVs) in metal oxides has been proved to be a powerful means for promoting the activation of CO₂. However, the lack of effective methods for OVs implantation currently hampers the rational design of highly-active CO₂ reduction catalysts. Herein, we reported a novel non-equilibrium photochemical strategy for preparing OV-rich Co₃O₄ at ambient temperature and pressure. Results confirm that the single isolated OV and Co-OV associates are the predominant defect types within Co₃O₄ skeleton. Moreover, the OVs concentration in Co₃O₄ can be tuned over a wide range by merely controlling the light-irradiation time. The experiments and theoretical calculations reveal that the OVs can promote the adsorption/activation of CO₂ and water, while considerably lowering the free energy barrier for COOH* formation, thereby accelerating the reaction kinetics. The OV-rich Co₃O₄ displays a 26.7-fold improvement in CO₂ reduction activity over the OV-poor Co₃O₄. The turnover frequency of Co atoms in OV-rich Co₃O₄ reaches 3.754 s⁻¹, which is one of the best reported catalysts for CO₂ photoreduction to date. Moreover, we also successfully synthesize a series of defect-rich metal oxides and metal sulfides using this photochemical method, such as TiO₂, Fe₂O₃, CuO, Mn₃O₄, CeO₂, V₂O₅, MoO₃, ZrO₂, Bi₂O₃, MoS₂, MnS, CdS, NiS₂-Ni₃S₄ and Bi₂S₃-BiS₂, which suggests its universality. We believe this photochemical method developed herein greatly enriches the knowledge for the synthesis of defective nanocrystals under mild synthesis conditions. Importantly, the relationship between the OVs and the CO₂ reduction performance has been established by various characterizations, which may guide the design of highly-efficient catalysts for CO₂ photofixation.

在金属氧化物中引入氧空位 (OVs) 已被证明是促进 CO ₂活化的有力手段。然而，目前缺乏有效的OVs植入方法阻碍了高活性CO ₂还原催化剂的合理设计。在此，我们报道了一种在环境温度和压力下制备富含 OV 的 Co ₃ O ₄的新型非平衡光化学策略。结果证实，单个孤立的 OV 和 Co-OV 关联是 Co ₃ O ₄骨架内的主要缺陷类型。此外，Co ₃ O _{4 中}的OVs浓度仅通过控制光照射时间就可以在很宽的范围内进行调谐。实验和理论计算表明，OVs 可以促进 CO ₂和水的吸附/活化，同时显着降低 COOH* 形成的自由能垒，从而加速反应动力学。与缺乏 OV 的 Co ₃ O ₄相比，富含 OV 的 Co ₃ O _{4 的}CO ₂还原活性提高了 26.7 倍。Co 原子在富含 OV 的 Co ₃ O _{4 中}的周转频率达到 3.754 s ^-1，这是报道最好的 CO ₂催化剂之一迄今为止的光还原。此外，我们还利用这种光化学方法成功合成了一系列富含缺陷的金属氧化物和金属硫化物，如TiO ₂、Fe ₂ O ₃、CuO、Mn ₃ O ₄、CeO ₂、V ₂ O ₅、MoO ₃、 ZrO ₂、Bi ₂ O ₃、MoS ₂、MnS、CdS、NiS ₂ -Ni ₃ S ₄和 Bi ₂ S ₃ -BiS ₂，这表明它的普遍性。我们相信本文开发的这种光化学方法极大地丰富了在温和合成条件下合成有缺陷的纳米晶体的知识。重要的是，OVs 和 CO ₂还原性能之间的关系已经通过各种表征建立，这可以指导用于 CO ₂光固定的高效催化剂的设计。