Photocatalytic CO₂ reduction holds promise for mitigating global warming and achieving carbon neutrality. Metal–organic frameworks (MOFs) are particularly promising as photocatalysts due to their ability to tune metal–oxo cluster electronic structures and facilitate CO₂ adsorption. In this study, a chemically stable La-MOF modified with Ni-doped metal–oxo clusters has been synthesized through a one-pot solvothermal reaction. Experimental and in situ test results show that the introduction of Ni atoms leads to the formation of oxygen vacancies (VOs) induced by the unsaturated coordination of La/Ni-MOF, which facilitates the adsorption and activation of CO₂. The electronic structure of metal–oxo (La–O) clusters is also effectively regulated, which enhances the electron-accepting ability of La–O clusters and promotes the photo-induced electron transfer from the lowest unoccupied molecular orbital (LUMO) of the electron donor to the conduction band (CB) of La-MOF. In addition, the built-in metal atom (Ni) acts as an active site for CO₂ adsorption and activation, achieving effective charge transfer and activated CO₂ adsorption integrated construction. Interestingly, LSV electrochemical tests showed that the onset potential of the La/Ni-MOF-3 electrode in the CO₂ bubbling system was lower than that of the N₂ bubbling system, indicating that CO₂ reduction proceeds preferentially to H₂ reduction. The synergy of these effects leads to the optimal La/Ni-MOF with a CO selectivity of 96.8% and a yield of 669.3 μmol g⁻¹, which is 2.5-fold and more than 5-fold as high as that of the pure La-MOF and Ni-MOF, respectively. This work provides a facile but efficient strategy for the construction of coordination unsaturated metal sites and VOs as well as the regulation of the electronic structure of MOFs as efficient photocatalysts towards enhanced performances.

中文翻译：

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一种非等效 Ni 掺杂 La-MOF，通过氧空位调节和电子结构优化来增强光催化 CO2 还原


光催化 CO₂ 减排有望缓解全球变暖和实现碳中和。金属有机框架 （MOF） 作为光催化剂特别有前途，因为它们能够调节金属-羰基簇电子结构并促进 CO₂ 吸附。在这项研究中，通过一锅法溶剂热反应合成了一种化学稳定的 La-MOF，该 La-MOF 由掺镍金属-氧基团簇修饰。实验和原位测试结果表明，Ni 原子的引入导致 La/Ni-MOF 的不饱和配位诱导的氧空位 （VO） 的形成，从而促进 CO₂ 的吸附和活化。金属-氧代 （La-O） 团簇的电子结构也受到有效调节，增强了 La-O 团簇的电子接受能力，促进了光诱导电子从电子供体的最低未占据分子轨道 （LUMO） 转移到 La-MOF 的导带 （CB）。此外，内置金属原子 （Ni） 作为 CO₂ 吸附和活化的活性位点，实现有效的电荷转移和活化的 CO₂ 吸附一体化构建。有趣的是，LSV 电化学测试表明，CO₂ 鼓泡系统中 La/Ni-MOF-3 电极的起始电位低于 N₂ 鼓泡系统，表明 CO₂ 还原优先于 H₂ 还原。这些效应的协同作用导致了最佳的 La/Ni-MOF，其 CO 选择性为 96.8%，产率为 669。3 μmol ^g-1，分别是纯 La-MOF 和 Ni-MOF 的 2.5 倍和 5 倍多。这项工作为构建配位不饱和金属位点和 VOs 以及调节 MOF 的电子结构作为有效的光催化剂以提高性能提供了一种简单而有效的策略。