Single-atom Fe–N–C materials with Fe–N₄ coordination structures, hailed as promising catalysts, are prohibited by the severe aggregation and migration of metal atoms. Although bonding-confinement strategies can be used to effectively regulate and strengthen the coordination of isolated metal atoms, the precise control of the coordination environment of metal centers remains a challenge. Herein, we report a rational strategy by which to bond iron phthalocyanine (FePc) on pre-synthesized Fe–N–C materials to further obtain anatomically dispersed Fe–N₄ catalysts. The axial coordination of O-FeN₄ sites to form a Fe–O–Fe bridge bond lowers the overpotential for the oxygen reduction reaction (ORR). Incorporation of the O atom stimulates the adsorbed O₂ to obtain more electrons, thereby enhancing the adsorption and activation of O₂. The catalyst demonstrates a half-wave potential of 0.866 V (versus RHE) and kinetic current density of 11.49 mA cm⁻², significantly outperforming commercial Pt/C. The primary Zn–air battery assembled with such a catalyst exhibits a high current density of 136 mA cm⁻² @ 1.0 V and a maximum power density of 205 mW cm⁻², supporting its potential feasibility in practical applications. Our findings provide a new avenue for tuning the coordination environment of single-atom catalysts to enhance their ORR activity.

中文翻译：

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通过在单原子铁催化剂上制作桥键氧配体促进氧还原

_{具有 Fe-N 4}配位结构的单原子 Fe-N-C 材料被誉为有前景的催化剂，但由于金属原子的严重聚集和迁移而受到阻碍。虽然键约束策略可以有效地调节和加强孤立金属原子的配位，但精确控制金属中心的配位环境仍然是一个挑战。在此，我们报告了一种合理的策略，通过该策略将铁酞菁 (FePc) 键合在预合成的 Fe-N-C 材料上，以进一步获得解剖学上分散的 Fe-N ₄催化剂。O-FeN ₄位点的轴向配位形成 Fe-O-Fe 桥键降低了氧还原反应 (ORR) 的过电位。O原子的结合刺激吸附的O ₂以获得更多的电子，从而增强O ₂的吸附和活化。该催化剂表现出 0.866 V 的半波电位（相对于RHE）和 11.49 mA cm ^-2的动态电流密度，显着优于商业 Pt/C。用这种催化剂组装的一次锌空气电池在1.0 V时具有 136 mA cm ^{-2的高电流密度和 205 mW cm -2}的最大功率密度，支持其在实际应用中的潜在可行性。我们的研究结果为调整单原子催化剂的配位环境以提高其 ORR 活性提供了新途径。