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.