Porphyrin-based metal–organic frameworks (MOFs) are ideal platforms for heterogeneous photocatalysts toward CO₂ reduction. To further explore photocatalytic MOF systems, it is also necessary to consider their ability to fine-tune the microenvironments of the active sites, which affects their overall catalytic operation. Herein, a kind of ionic liquid (IL, here is 3-butyric acid-1-methyl imidazolium bromide, BAMeImBr) was anchored to iron-porphyrinic Zr-MOFs with different amounts to obtain ILx@MOF-526 (MOF-526 = Zr₆O₄(OH)₄(FeTCBPP)₃, FeTCBPP = iron 5,10,15,20-tetra[4-(4′-carboxyphenyl)phenyl]-porphyrin, x = 100, 200, and 400). ILx@MOF-526 series was designed to investigate the effects of the microenvironmental and electronic structural modification on the efficiency and selectivity of the photochemical reduction of CO₂ after introducing IL fragments. Compared to parent MOF-526, the production and selectivity of CO were greatly improved in the absence of any photosensitizer under visible light by the ILx@MOF-526 series. Among them, the CO yield of IL200@MOF-526 was up to 14.0 mmol g^–1 within 72 h with a remarkable CO selectivity of 97%, which is superior to that of MOF-526 without BAMeIm⁺ modification and other amounts of BAMeIm⁺ loaded. Furthermore, density functional theory calculations were performed to study the mechanism of the CO₂ reduction.

中文翻译：

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离子液体改性铁卟啉金属有机骨架作为高效、选择性光催化剂用于二氧化碳减排


卟啉基金属有机骨架（MOF）是异质光催化剂 CO ₂ 还原的理想平台。为了进一步探索光催化MOF系统，还需要考虑其微调活性位点微环境的能力，这会影响其整体催化操作。本文将一种离子液体（IL，此处为3-丁酸-1-甲基溴化咪唑鎓，BAMeImBr）锚定到不同量的铁卟啉Zr-MOFs上，得到ILx@MOF-526（MOF-526 = Zr ₆ O ₄ (OH) ₄ (FeTCBPP) ₃ , FeTCBPP = 铁 5,10,15,20-tetra[4 -(4'-羧基苯基)苯基]-卟啉，x = 100、200 和 400)。 ILx@MOF-526系列旨在研究引入IL片段后微环境和电子结构修饰对CO ₂ 光化学还原效率和选择性的影响。与母体MOF-526相比，ILx@MOF-526系列在可见光下无任何光敏剂的情况下CO的产量和选择性得到了极大的提高。其中，IL200@MOF-526在72 h内CO产率高达14.0 mmol g ^–1 ，CO选择性高达97%，优于不含BAMeIm的MOF-526 ⁺ 修改和加载其他数量的 BAMeIm ⁺ 。此外，还进行了密度泛函理论计算来研究CO ₂ 还原的机理。