Intermetallic Cu11In9in situ formed on hierarchical nanoporous Cu for highly selective CO2 electroreduction

Abstract

Developing highly selective and cost-effective electrocatalysts is crucial for the efficient conversion of CO₂ to value-added carbon products. Here, we report intermetallic Cu₁₁In₉ nanoparticles that are in situ formed on nanoporous Cu skeleton (Cu₁₁In₉/Cu) as highly selective and electroactive catalysts to mediate CO₂ electroreduction to CO. Owing to the high oxophilicity of surface indium atoms, their spontaneous hydroxylation results in the formation of heterogeneous Cu–In(OH)_x surface on monoclinic Cu₁₁In₉ nanoparticles, which selectively boosts reaction kinetics of CO₂-to-CO conversion as a result of weakening adsorption energies of *CO and H* intermediates on surface Cu atoms. Associated with hierarchical nanoporous Cu architecture to offer a high specific surface area for full use of electroactive sites and facilitate electron and mass transports along interconnective Cu ligaments and interpenetrative nanopores, nanoporous Cu₁₁In₉/Cu hybrid electrodes exhibit exceptional electrocatalysis for CO product, with a high partial current density of 12.6 mA cm_geo⁻² and high faradaic efficiency of 92.8%, as well as excellent stability for more than 240 h at an overpotential of 0.49 V. These outstanding electrochemical properties make them attractive alternatives to precious Au- and Ag-based electrocatalysts for high-performance CO₂ electrolysers.