Tailoring frustrated Lewis pair catalysts for enhanced electrochemical CO₂ reduction to multi-carbon fuels

Electrochemical reduction of CO₂ to value-added chemical fuels is crucial for closing the anthropogenic carbon cycle and storing renewable energy; however, the development of a highly active and selective catalyst remains a significant challenge. Currently, CO₂ reduction to hydrocarbons (especially C₂ products) mainly relies on copper (Cu)-based catalysts, which often face considerable obstacles, including high energy barriers for C-C coupling and low product selectivity. In this study, we propose an innovative approach by introducing a metal-free frustrated Lewis pair (FLP) catalyst that utilizes the (110) surface of boron phosphide (BP) and boron arsenide (BAs) based on extensive first-principles calculations. Our findings reveal that these surface FLPs of BP and BAs (110) exhibit remarkable stability in electrochemical environments and efficiently capture and activate CO₂ molecules through Lewis acid-base interactions. The "push-pull effect" facilitates the reduction of captured CO₂ into CH₄ and C₂H₆, featuring ultra-low potential-determining steps (PDS) of 0.11 and 0.28 eV, respectively. Furthermore, the unwanted competitive reaction, i.e. the hydrogen evolution reaction (HER), can be significantly suppressed during CO₂ reduction, enhancing the selectivity for desired products. Overall, such a low PDS has never been achieved on any previously reported CO₂ reduction catalysts, highlighting the potential of FLPs as a promising strategy for improving the catalytic performance of CO₂ reduction reactions.