Copper-tetracyanoquinodimethane-derived copper electrocatalysts for highly selective carbon dioxide reduction to ethylene

As one of the most promising CO₂ utilization techniques, electrochemical CO₂ reduction has recently received considerable attention. Cu is a unique electrocatalyst that can convert CO₂ to value-added multi-carbon chemicals. Nevertheless, Cu catalysts are always limited by the poor selectivity and stability. Here, we report that using copper-tetracyanoquinodimethane (CuTCNQ) derived Cu nanoparticles as efficient electrocatalysts for conversion of CO₂ to ethylene characteristic with high selectivity and stability, showing 56% Faradaic efficiency (FE) to C₂H₄ at −1.3 V vs. reversible hydrogen electrode (RHE). Upon the electrochemical CO₂ reduction, CuTCNQ slowly reconstructs to Cu nanoparticles with abundant grain boundaries and residual Cu⁺ on the surface. Theoretical calculation and operando characterization disclose that both as-formed Cu nanoparticle grain boundaries and residual Cu⁺ endow the catalyst with high selectivity toward ethylene. Furthermore, during the reconstruction of CuTCNQ to Cu nanoparticles, the grain boundaries Cu surface is slowly refreshed by continual addition of Cu atoms, thus inhibiting the surface passivation and guaranteeing the electrocatalytic stability.