Nanoporous Intermetallic Cu3Sn/Cu Hybrid Electrodes as Efficient Electrocatalysts for Carbon Dioxide Reduction

Abstract Designing highly selective and cost‐effective electrocatalysts toward electrochemical carbon dioxide (CO 2 ) reduction is crucial for desirable transformation of greenhouse gas into fuels or high‐value chemical products. Here, the authors report intermetallic Cu 3 Sn that is in situ formed and seamlessly integrated on self‐supported bimodal nanoporous Cu skeleton (Cu 3 Sn/Cu) via a spontaneous alloying of Sn and Cu as robust electrocatalyst for selective electroreduction of CO 2 to CO. By virtue of Sn atoms strengthening CO adsorption on Cu atoms, the intermetallic Cu 3 Sn has an intrinsic activity of ≈10.58 μA cm −2 , more than 80‐fold higher than that of monometallic Cu. By virtue of hierarchical bicontinuous nanoporous Cu architecture facilitating electron transfer and CO 2 and proton mass transport and offering high specific surface areas for full use of electroactive Cu 3 Sn sites, the nanoporous Cu 3 Sn/Cu hybrid electrodes produce CO at a low overpotential of 0.09 V, and exhibit high partial current density of ≈15 mA cm −2 geo at overpotential of 0.59 V, along with excellent stability and selectivity of 91.5% Faradaic efficiency. The outstanding electrochemical performance make them attractive alternatives to precious Au‐ and Ag‐based electrocatalysts for building low‐cost CO 2 electrolyzers to selectively produce CO.