The p-Orbital Delocalization of Main-Group Metals to Boost CO2 Electroreduction

Enhancing the p-orbital delocalization of a Bi catalyst (termed as POD-Bi) via layer coupling of the short inter-layer Bi-Bi bond facilitates the adsorption of intermediate *OCHO of CO2 and thus boosts the CO2 reduction reaction (CO2RR) rate to formate. X-ray absorption fine spectroscopy shows that the POD-Bi catalyst has a shortened inter-layer bond after the catalysts are electrochemically reduced insitu from original BiOCl nanosheets. The catalyst on a glassy carbon electrode exhibits a record current density of 57 mA cm(-2) (twice the state-of-the-art catalyst) at -1.16V vs. RHE with an excellent formate Faradic efficiency (FE) of 95%. The catalyst has a record half-cell formate power conversion efficiency of 79% at a current density of 100 mA cm(-2) with 93% formate FE when applied in a flow-cell system. The highest rate of the CO2RR production reported (391 mgh(-1) cm(2)) was achieved at a current density of 500 mA cm(-2) with formate FE of 91% at high CO2 pressure.