Confinement-Balanced CO ₂ Adsorption and Activation over Ultrasonically Assembled CuO/Carbon Nitride Catalysts for Enhanced C ₂ H ₄ Selectivity from CO ₂ Electroreduction

Abstract

Balancing adsorption and activation of carbon dioxide (CO₂) reactants as well as inhibiting competitive hydrogen evolution reaction (HER) are critical for boosting the CO₂ electrocatalytic reduction to ethylene (C₂H₄), yet the design of efficient catalysts with such capabilities remains a great challenge. In this work, we present a hybrid catalyst with CuO nanosheets intercalating with pyridine nitrogen-rich carbon nitride (CN) catalyst (CuO/CN) via an ultrasonically assembled method. The catalyst with an optimal mass ratio of CuO to CN of 1:5 exhibits a maximum C₂H₄ Faraday efficiency (FE_C2H4) of 52% for the CO₂ reduction reaction, outperforming that of CuO alone (38%). The introduction of hydrophobic CN endows this hybrid CuO/CN with locally distinguished CO₂ enrichment and utilization of surface-active hydrogen species, which enables the reconstructed active Cu/CuO interface with a well-balanced adsorption and activation of CO₂ for maximizing C-C coupling efficiency, thus greatly enhancing the FE_C2H4. Such a confinement-promoted CO₂ adsorption-activation equilibrium strategy will give a useful clue for the design of efficient CO₂-to-C₂H₄ electrocatalysts.