Fluorine-Mediated Interfacial Microenvironment for Boosting pH-Universal CO2 Reduction.

Abstract

Achieving highly efficient and stable conversion of carbon dioxide reduction reaction (CO₂RR) into value-added chemicals at industrial current density is crucial but challenging due to its complex gas-solid-liquid interface. Here the local microenvironment of three-phase interface is successfully regulated to boost the CO₂RR performance of Ni species in the universal pH range by introducing the highly electronegative F. The optimized Ni/FC achieves high-performance in converting CO₂ to CO with Faraday efficiencies (FEs) over 90% in pH-universal conditions, while the main product of Ni/C is H₂, especially under acidic conditions. Significantly, it can steadily operate at a high current density of 200 mA cm^-2 for over 3000 h in a broad pH range, outperforming most recently reported CO₂RR electrocatalysts. Detail in situ experiments and density functional theory calculations reveal that the presence of highly electronegative F will cause the formation of a positive C^δ+ center, which inhibits the adsorption of hydrogen and increases the dissociation energy barrier of interfacial water, thereby suppressing the competitive hydrogen evolution reaction (HER). This work highlights the importance of regulating the local microenvironment of interfacial water, providing a new perspective in the field of electrocatalysis for suppressing competitive HER.