High-performance carbon dioxide reduction to multi-carbon products on EDTA-modified Cu-Ag tandem catalyst

Tandem catalysts are able to sequential reduction of CO2 to multi-carbon (C2+) on their adjacent complement hetero active sites. However, Faraday efficiency of C2+ on these catalysts is limited by inefficient modulation of local pH. Herein, we systematically design ethylenediaminetetraacetic acid (EDTA) modified Cu-Ag catalysts for reduction of CO2 to C2+ products with highly selectivity. After introducing EDTA, surface Cu atoms possess well-defined valence and coordination environments, giving improved electronic configuration for intermediate adsorption. During electrochemical reaction, amine groups shows strong ability to regulate local pH and thus facilitates reaction kinetics. Correspondingly, several important intermediates that related to formation of C2+ on adjacent active sites are observed in in-situ Raman spectra. CuAg4/EDTA shows high activity for C2+ products, with total FEC2+ of 86.56 % at applied potential of-1.23 V vs. RHE. This unique protocol is expected to provide a scientific basis for expanding functional ligand in regulating microenvironment of catalysts.