Multi-Element Alloying and High-Entropy-Driven Catalytic Site Engineering: CuNiCoFeMn@KB High-Entropy Alloy Achieves High Efficiency for Electroreduction of CO2 to C2H5OH

Abstract

Electrochemical carbon dioxide reduction reactions (CO₂RR) offer a promising technological pathway for addressing greenhouse gas emissions, yet their complex reaction pathways and challenges in controlling product selectivity remain significant hurdles. In this study, a CuNiCoFeMn@KB high-entropy alloy (HEA) catalyst was successfully synthesized via a one-pot solvothermal reduction strategy. Structural and theoretical analyses suggest that the multi-element alloying and high-entropy-like configuration alter the local surface composition and synergistically modulate the electronic structure, inducing an upshift of the d-band center, which significantly enhances the adsorption of key reaction intermediates. Electrochemical evaluations demonstrated that the catalyst achieves a Faradaic efficiency of 57.3% for ethanol at −0.75 V versus RHE, with a current density of 32.83 mA cm⁻² at −0.95 V, while maintaining robust long-term stability exceeding 120 h. The regulatory mechanism of configurational entropy on CO₂RR pathways was systematically investigated through a combination of density functional theory (DFT) calculations and experimental validation. Theoretical results indicate that *OCCO serves as the pivotal intermediate in the ethanol formation pathway. An increase in ΔS_conf improves the thermodynamic preference for *OCCO dimerization, conferring a thermodynamic advantage for C─C coupling. This provides a potential “entropy regulation-adsorption energy-reaction pathway” correlation model. This work offers valuable theoretical insights and a promising material platform for the rational design of highly efficient catalysts for CO₂RR.