Domain‐Confined Etching Strategy to Regulate Defective Sites in Carbon for High‐Efficiency Electrocatalytic Oxygen Reduction

Abstract Coupling sites of nitrogen dopants and intrinsic carbon defects (N/DC) in metal‐free carbon are highly active toward electrocatalytic oxygen reduction reaction (ORR), and yet they are hard to be effectively constructed. Here, a novel synthesis strategy for fabrication of N/DC‐enriched metal‐free carbon from precursors containing metal‐nitrogen moieties (M‐N x ) is reported. During pyrolysis of the precursors, the M‐N x is in situ converted to endogenous metal oxides (MO x ) via a halide‐mediated “bait and switch” mechanism to realize a domain‐confined etching of the carbon matrix around the nitrogen dopants, forming abundant N/DC coupling sites in the final carbon products. The optimized N/DC‐enriched carbon exhibits an outstanding ORR activity and stability with a half‐wave potential of 0.903 V (versus RHE) in 0.1 m KOH solution, outperforming most of the reported metal‐free carbon catalysts. Experimental investigations and theoretical calculations demonstrate an improved electron‐donating ability and optimized binding energies of the N/DC coupling sites toward the ORR intermediates, which are primarily responsible for such an excellent ORR activity. This domain‐confined endogenous MO x etching strategy is also widely applicable to different M‐N x ‐containing precursors as well as different halide mediators, which opens up new possibilities to fabricate metal/nonmetal doped carbon materials enriched with various coupling sites of desired synergistic properties.