Atomically dispersed Fe–N–C catalyst has shown great performance in the CO-to-CO conversion, yet the high CO selectivity is achieved only within a rather narrow potential range, which cannot well meet the requirements for the following CO dimerization or hydrogenation. Here, we developed a hydrogen-pyrolysis etching strategy to precisely manipulate the uncoordinated N dopants in the Fe–N–C catalyst. This strategy could preferentially eliminate pyridinic and pyrrolic N atoms while leaving graphitic N. The resulting catalyst gave a CO faradaic efficiency (FE) above 90% over a broad window from −0.3 to −0.8 V (versus RHE) (in particular, FE > 97% at −0.6 V). In situ ATR-SEIRAS and first-principle calculations further revealed that this strategy can not only suppress the parasitic H generation but also promote CO activation and protonation with the assistance of co-adsorbed HO on the “atomic interface” of “FeN/graphitic N.”