Boosting CO2 electroreduction to HCOOH at high current density through tuning the electronic metal-support interaction

Electrocatalytic CO2 reduction (CO2ER) to valuable chemicals, for example, HCOOH have received widespread attention, which still suffers from moderate Faradaic efficiency with low current regarding the wide industrial application of HCOOH. Herein, we employed a strategy of modifying electronic metal-support interaction (EMSI) by fabricating Bi nanoparticles supported Ni-modified Bi2O2CO3 (Bi/Ni-BOC) heterostructure. The obtained Bi/Ni-BOC exhibited high formate Faradic efficiency (FEHCOOH) of 97% at -2.1 V (vs. Ag/AgCl) and above 90% within broad potential range (-1.7 to -2.2 V) in flow cell with superior stability at high current density of similar to 220 mA cm(-2), and formate concentration can reach 2.4 mmol h(-1) cm(-2) at -2.3 V. In/ex situ x-ray absorption fine structure (XAFS) and density functional theory (DFT) calculation indicated that Ni doping promoted the enhancement of EMSI, which improved the generation and stable existence of electron-rich Bi to boost CO2 activation and *OHCO hydrogenation, thus facilitating highly-efficient formate production with hydrogen evolution reaction (HER) inhibition.