Electroreduction of CO₂ into value-added chemical feedstocks is a highly promising approach to alleviating environmental problems and achieving a global carbon neutral economy. Among the various CO₂ reduction products, alcohol (EtOH) is considered the most important liquid fuel due to its wide range of applications and remarkable energy density. However, highly selective production of EtOH from electrochemical CO₂ reduction reaction (eCO₂RR) is very challenging because of the sluggish asymmetric C−C coupling reaction and competition of ethylene production. Therefore, it is urgently necessary to develop more efficient catalysts and to improve the understanding of the mechanisms that promote EtOH production from eCO₂RR. Metal-organic frameworks (MOFs) with periodic framework structures and well-defined metal active sites are considered as good platforms for catalyst design. We successfully constructed a MOF catalyst with heterometallic Sn-Cu dual sites, namely CuSn-HAB, by anchoring a tin ion with a stronger affinity to O atom to serve as the second active site aside the Cu site through a post-synthetic modification strategy. This novel oxygen coordination mode on the heterometallic dual site avoids the premature hydrogenation of oxygenate intermediates during the eCO₂RR, preserving the C−O bonds and thus improving the selectivity of ethanol as liquid product. Our results provide valuable insights into the rational design of the electrocatalysts and the modulation of product selectivity in the eCO₂RR process.

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Jia-Run Huang

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