Copper atom-pair catalyst anchored on alloy nanowires for selective and efficient electrochemical reduction of CO₂

The electrochemical reduction of CO₂ could play an important role in addressing climate-change issues and global energy demands as part of a carbon-neutral energy cycle. Single-atom catalysts can display outstanding electrocatalytic performance; however, given their single-site nature they are usually only amenable to reactions that involve single molecules. For processes that involve multiple molecules, improved catalytic properties could be achieved through the development of atomically dispersed catalysts with higher complexities. Here we report a catalyst that features two adjacent copper atoms, which we call an 'atom-pair catalyst', that work together to carry out the critical bimolecular step in CO₂ reduction. The atom-pair catalyst features stable Cu₁⁰-Cu₁^x+ pair structures, with Cu₁^x+ adsorbing H₂O and the neighbouring Cu₁⁰ adsorbing CO₂, which thereby promotes CO₂ activation. This results in a Faradaic efficiency for CO generation above 92%, with the competing hydrogen evolution reaction almost completely suppressed. Experimental characterization and density functional theory revealed that the adsorption configuration reduces the activation energy, which generates high selectivity, activity and stability under relatively low potentials.