Copper-Catalysed Electrochemical CO2 Methanation via the Alloying of Single Cobalt Atoms

Abstract

The electrochemical reduction of carbon dioxide (CO₂) to methane (CH₄) presents a promising solution for mitigating CO₂ emissions while producing valuable chemical feedstocks. Although single-atom catalysts have shown potential in selectively converting CO₂ to CH₄, their limited active sites often hinder the realization of high current densities, posing a selectivity-activity dilemma. In this study, we developed a single-atom cobalt (Co) doped copper catalyst (Co₁Cu) that achieved a CH₄ Faradaic efficiency exceeding 60 % with a partial current density of −482.7 mA cm⁻². Mechanistic investigations revealed that the incorporation of single Co atoms enhances the activation and dissociation of H₂O molecules, thereby lowering the energy barrier for the hydrogenation of *CO intermediates. In situ spectroscopic experiments and density functional theory simulations further demonstrated that the modulation of the *CO adsorption configuration, with stronger bridge-binding, favours deep reduction to CH₄ over the C−C coupling or CO desorption pathways. Our findings underscore the potential of Co₁Cu catalysts in overcoming the selectivity-activity trade-off, paving the way for efficient and scalable CO₂-to-CH₄ conversion technologies.