Integrated Electrochemical Carbon Capture and Utilization by Redox-Active Amine Grafted Gold Nanoparticles

Electrochemical carbon capture and utilization (eCCU) from flue gas CO2 could avoid high energy consumption and capital input in conventional capture, storage, and utilization, which is a promising approach for achieving negative emissions and producing "e-chemicals." However, low CO2 concentration and leftover O2 in the flue gas presumably lowers the eCCU performance. Herein, redox-active 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) functionalized gold nanoparticles are synthesized to achieve integrated electrochemical capture and reduction of CO2 in simulated flue gas (SFG, 15% CO2, 4% O2, balanced with N2), achieving maximum CO Faradaic efficiency of 80.2% at -0.45 V versus RHE in H-type cell, and 66.0% at voltage of 2.7 V in a full cell, respectively. The AMT ligand can capture CO2 by strong interaction with CO2 in the reduced state and serve as a selective layer to suppress O2 reduction, which provides the ability of electrochemical carbon capture from SFG and significantly decreases energy required for CO2 electro-reduction. Integrated electrochemical CO2 capture and utilization using redox-active amine combined with Au catalyst is presented to realize direct utilization of flue gas. Reduced 2-amino-5-mercapto-1,3,4-thiadiazol can capture CO2 from flue gas, and captured CO2 in the reduced carbamate form is pre-activated compared to neutral CO2, and then it can be more efficiently reduced by the Au catalyst to form CO, achieving in situ CO2 capture and utilization.image