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).

单金属原子和内部结构缺陷不可避免地共存于由基本热解过程制备的 M-N-C 催化剂中，但迄今为止建立它们的协同相关性以实现有效的催化性能并显示构效关系仍然很困难。在此，进行了 Ag-N-C 电催化剂的原位 N 缺陷和单 Ag 原子协同工程，以说明它们在热解过程中的共生形成。结构分析和计算表明，通过选择性 C/N-Ag 和 C-N 键断裂，在 Ag-N-C 中产生了具有相邻 N 缺陷的边缘承载的 Ag-N _3位点。同时，在 KHCO ₃电解质中，K ⁺阳离子倾向于吸附在 Ag-N-C 的 N 缺陷位点，静电锚定 HCO ₃ ^-阴离子以促进 CO ₂分子在 Ag N ₃位点上的吸附和攻击。这种协同效应促进了碳酸氢盐种类的产生，随后的 *COOH 中间体在 - 0.95 V (vs RHE) 下表现出高达 95.21% 的 CO 法拉第效率。