Activation and electrochemical reduction of carbon dioxide by transition metal atom-doped copper clusters

Abstract

The conversion of CO₂ into valuable chemical products has garnered significant interest due to the pressing need for sustainable solutions. Central to achieving this goal is the development of efficient and cost-effective catalysts. Although Cu is one of the most promising materials for CO₂ reduction, it lacks selectivity. In this study, we explore the effect of doping on the binding affinity and activation of CO₂ by focusing on XCu₁₂ clusters, where X represents 3d and 4d transition metal atoms. By employing a multi-scale theoretical approach that integrates the artificial bee colony algorithm, an extended tight binding model, and density functional theory (DFT), the lowest energy geometries of XCu₁₂ clusters were determined, revealing that the dopant X-atoms favour endohedral positions, preserving a cage-like structure and maximizing their coordination with the outer Cu-atoms. A thorough analysis of the structural, electronic, and magnetic properties elucidates the varying capabilities of these clusters for the electrochemical reduction of CO₂ to CO. Doping of transition metal atoms is found to significantly modify the electronic and magnetic properties of the clusters, enhancing their reactivity towards CO₂. A significant reduction of about 20% in overpotential for CO₂ reduction is observed in doped clusters compared to the pure Cu₁₃ cluster. An empirical formula is proposed by fitting the DFT data using ordinary least squares (OLS) regression. This comprehensive study provides fundamental insights into the potential of bimetallic copper clusters for CO₂ activation and reduction, emphasizing their role in advancing catalytic processes for sustainable chemical production.