In-situ N-defect and single-metal atom synergetic engineering of high-efficiency Ag–N–C electrocatalysts for CO2 reduction

Single-metal atoms and inner structural defects inevitably coexist in M–N–C catalysts prepared from the essential pyrolysis process, but establishing their synergistic correlation to achieve efficient catalytic performance and manifest the structure-activity relationship are yet difficult so far. Herein, the in-situ N-defect and single-Ag atom synergetic engineering of Ag–N–C electrocatalysts is performed to illustrate their symbiotic formation during pyrolysis. The structural analysis and calculations demonstrate the creation of edge-hosted Ag–N3 sites with adjacent N-defects in the Ag–N–C through the selective C/N–Ag and C–N bond cleavages. Meanwhile, in a KHCO3 electrolyte, K+ cations tend to adsorb at the N-defect sites of Ag–N–C, which electrostatically anchor HCO3− anions to facilitate the adsorption and attack of CO2 molecules on AgN3 site. This synergistic effect promotes the generation of bicarbonate species and subsequent *COOH intermediates exhibits a high Faraday efficiency of CO up to 95.21% at − 0.95 V (vs RHE). [Display omitted] •Discovered symbiotic formation both edge-hosted Ag-N3 site and adjacent N-defect during pyrolysis in Ag-N-C.•Ag-N-C catalysis demonstrated an excellent catalysis activity of 95.21% FECO for CO2RR.•The synergistic effect of K+ cations trapped at N-defect and AgN3 site for CO2RR.