Precise Engineering of Multimetal Sites in Metal–Organic Frameworks for Efficient and Selective Electrochemical Reduction of CO ₂ to C ₂ and Urea Products

ConspectusThe electrochemical carbon dioxide reduction reaction (eCO₂RR) is a promising technology for reducing carbon emissions and producing valuable multicarbon and nitrogen-containing chemicals from CO₂. Among these, C₂ products such as ethylene (C₂H₄), ethanol (EtOH), acetate (AcO⁻)/acetic acid (AcOH), and urea are of particular interest due to their industrial value. The key to achieving these products lies in controlling C-C and C-N bond coupling, particularly by regulating the adsorption energy and geometry of the reaction intermediates. Compared to single-metal catalysts, multimetal systems offer better control over these intermediates through spatial configurations and adjustable adsorption properties, enabling more selective C-C and C-N coupling. However, achieving high selectivity for the target product remains challenging due to complex interactions among reaction pathways, binding energies, and the dynamic electrochemical environment. To overcome this, it is essential to understand how metal types, metal site arrangements, and coordination environments influence intermediate activation. Metal-organic frameworks (MOFs) offer a unique platform for designing such catalysts due to their structural order and atomic-level tunability. This Account systematically summarizes the structural engineering strategies of multimetal catalysts based on MOFs in the eCO₂RR and categorizes them into three typical types: (1) Multicopper sites, which can promote C-C coupling reactions between *CO and *CHO intermediates and are conducive to the generation of C₂H₄; further optimization of the chemical microenvironment can significantly enhance catalytic efficiency. (2) Adjacent heterometal sites based on Cu and oxyphilic metal such as the Cu-Sn site, which display different affinities of distinct metal centers for C and O atoms in the eCO₂RR, achieving C-C coupling between *CO and *OCH₂ intermediates for the production of EtOH. (3) Cooperative Fe-based multimetallic sites, which take advantage of the strong nitrogen affinity of Fe sites and the CO₂ activation ability of Cu/Ni centers to promote selective C-N coupling for urea synthesis. The above structure-performance relationships provide theoretical basis and practical guidance for yielding target C₂ products or urea with high selectivity through eCO₂RR. This Account not only constructs a conceptual framework for the selective synthesis of C₂ compounds and urea starting from CO₂ but also highlights the flexibility and controllability of MOF-based multimetal catalysts as an ideal platform for CO₂ resource utilization and systematically provides guidance for the selective acquisition of specific complex products. Finally, we summarize several key design principles and future development directions, aiming to bridge the gap between a molecular-level understanding and practical device integration. To further enhance performance and deepen understanding of the catalytic mechanism, subsequent research is still needed to develop MOF-based electrocatalysts with more performance multimetallic site configurations and promote their application in industrial-related electrochemical manufacturing.