Grafting Amine-Functionalized Ligand Layer on Catalyst for Electrochemical CO2 Capture and Utilization

Direct electrochemical CO 2 capture and utilization from flue gas offers appealing route to closing the carbon cycle and avoiding the cost for CO 2 purification. Yet, the low CO 2 concentration in flue gas and competing oxygen reduction reaction (ORR) pose severe challenges for this process. Herein, we report 4-aminobutylphosphonic acid ligand layer capped Ag nanoparticles (NH 2 BPA-Ag) for high-efficiency conversion of simulated flue gas (SFG). The amino group in NH 2 BPA is available for CO 2 capture and activation, while phosphonic acid groups inhibit ORR by desorbing *OOH intermediate. NH 2 BPA-Ag achieves 82% CO Faradaic efficiency (FE CO ) in H-cell for SFG reduction and enhances FE CO 2.6 times over pristine Ag nanoparticles. In a membrane electrode assembly electrolyzer, NH 2 BPA-Ag shows 79.6% FE CO and 38.1% full-cell energy efficiency at 48   mA   cm -2 for SFG conversion. This study highlights the strategy of tailoring catalytic microenvironments at molecular level for realizing a highly selective performance.