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Heterogeneous electrocatalysis provides better control of the chemical surroundings of the catalyst's active site for improved performance, offers the possibility of overcoming drawbacks of deactivation caused by aggregation or dimerization in homogeneous condition, and permits the use of benign aqueous solutions. Employing metal−organic frameworks (MOFs) or covalent−organic frameworks (COFs) to support the active molecular catalyst of porphyrin for electrochemical conversion of CO 2 to CO is a promising strategy. We have rationally introduced a 3D highly stable porphyrin-based MOF of PCN-222(Fe) into heterogeneous catalysis through the simple dipcoating method. The composite catalyst PCN-222(Fe)/C (mass ratio = 1:2) exhibited high catalytic performance for electrochemical conversion of CO 2 to CO with 494 mV overpotential (where j = 1.2 mA cm −2 ) and maximum 91% FE CO in a CO 2 -saturated 0.5 M KHCO 3 aqueous solution, achieving a TOF of 0.336 site −1 s −1 . The catalyst was found to retain its crystallinity and stability after 10 h of electrolysis at −0.60 V versus RHE (average FE CO 80.4%; RHE, reversible hydrogen electrode), which generates 334 μmol of CO with the TOF of 0.012 s −1 (0.286 site −1 s −1 ). These results indicate that the PCN-222(Fe)/C has a substantial catalytic effect on the electrochemical reduction of CO 2 due to the combination of the intrinsic activity of the porphyrin molecule, and the promising CO 2 adsorption ability endowed by the conserved porosity, as well as the high conductivity of carbon black.

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Visible‐light driven photoconversion of CO2 into energy carriers is highly important to the natural carbon balance and sustainable development. Demonstrated here is the adenine‐dependent CO2 photoreduction performance in green biomimetic metal–organic frameworks. Photocatalytic results indicate that AD‐MOF‐2 exhibited a very high HCOOH production rate of 443.2 μmol g−1 h−1 in pure aqueous solution, and is more than two times higher than that of AD‐MOF‐1 (179.0 μmol g−1h−1) in acetonitrile solution. Significantly, experimental and theoretical evidence reveal that the CO2 photoreduction reaction mainly takes place at the aromatic nitrogen atom of adenine molecules through a unique o‐amino‐assisted activation rather than at the metal center. This work not only serves as an important case study for the development of green biomimetic photocatalysts used for artificial photosynthesis, but also proposes a new catalytic strategy for efficient CO2 photoconversion.

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