CO2 Electroreduction to Multicarbon Products in Acidic Electrolyte via Structural Reconstruction of a Molybdenum Porphyrin Dimer

The electrochemical reduction of CO2 into valuable hydrocarbon fuels offers a promising pathway for sustainable energy. This study develops a novel catalyst for this reaction: an oxo‐molybdenum dimer synthesized via a solid‐phase reaction, characterized by a central MoOMo bridging bond. The catalyst exhibits exceptional performance, selectively producing methanol with a high Faradaic efficiency of 74% at −1.0 V versus RHE. Notably, at a slightly more negative potential of −1.2 V versus RHE, it facilitates the critical step of carbon–carbon (CC) coupling, generating ethanol with 45% efficiency, a capability absent in monomeric control catalysts, underscoring the dimer's unique role. Mechanistic investigations using in situ FTIR and density functional theory (DFT) calculations reveal that methanol formation proceeds through key intermediates like *CHO and *CH2O at the tailored MoMo active sites. Isotope labeling with 13CO2 definitively confirms CO2 as the sole carbon source for both products. Overall, this work provides an efficient design strategy for molecular electrocatalysts, demonstrating how precise structural engineering of metal complexes can create active sites for the selective conversion of CO2 into multicarbon fuels.