PVP-stabilized intermediates promote C–C coupling for selective CO2 electroreduction to C2+ products on CuO catalysts

Abstract

The electrochemical carbon dioxide reduction reaction (CO₂RR) is an effective pathway for converting CO₂ into high-value chemicals. However, the original copper-based catalysts exhibit strong surface hydrophilicity and limited CO₂ adsorption capacity, resulting in low selectivity for C₂₊ products. In this study, we modify CuO catalysts with polyvinylpyrrolidone (PVP), significantly enhancing their selectivity for C₂₊ products. With a low amount of PVP (CuO@PVP1), the selectivity of the catalyst for ethylene (C₂H₄) at –1.6 V (vs. RHE) is 50.9%. Increasing the PVP content leads to a rise in alcohol production, with CuO@PVP2 reaching a selectivity of 72.8% for C₂₊ products. Besides, the C₂H₄ selectivity remains stable at 45% over 10 hours at –1.5 V (vs. RHE). The analysis based on in situ infrared indicates that the introduction of PVP enhances the adsorption capacity of CO₂, and can create a strong alkaline microenvironment, which suppresses H₂ release and lowers the formation barrier for the *OCCHO intermediate, thus facilitating C₂₊ product formation. Excessive PVP strengthens hydrogen bonding, aiding proton reactions and enabling the conversion of C₂H₄ into alcohols. This study clarifies how PVP influences the performance of CuO catalysts, offering a strategy for designing copper-based catalysts with improved selectivity for C₂₊ products.