Owing to their earth abundance, high atom utilization, and excellent activity, single iron atoms dispersed on nitrogen‐doped carbons (Fe‐N‐C) have emerged as appealing alternatives to noble‐metal platinum (Pt) for catalyzing the oxygen reduction reaction (ORR). However, the ORR activity of current Fe‐N‐C is seriously limited by the low density and inferior exposure of active Fe‐N_x species. Here, a novel zinc‐mediated template synthesis strategy is demonstrated for constructing densely exposed Fe‐N_x moieties on hierarchically porous carbon (SA‐Fe‐NHPC). During the thermal treatment of 2,6‐diaminopyridine/ZnFe/SiO₂ complex, the zinc prevents the formation of iron carbide nanoparticles and the SiO₂ template promotes the generation of hierarchically pores for substantially improving the accessibility of Fe‐N_x moieties after subsequent leaching. As a result, the SA‐Fe‐NHPC electrocatalysts exhibit an unprecedentedly high ORR activity with a half‐wave potential (E_1/2) of 0.93 V in a 0.1 m KOH aqueous solution, which outperforms those for Pt/C catalyst and state‐of‐the‐art noble metal‐free electrocatalysts. As the air electrode in zinc–air batteries, the SA‐Fe‐NHPC demonstrates a large peak power density of 266.4 mW cm⁻² and superior long‐term stability. Therefore, the developed zinc‐mediated template synthesis strategy for boosting the density and accessibility of Fe‐N_x species paves a new avenue toward high‐performance ORR electrocatalysts.

中文翻译：

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锌介导的Fe‐N‐C电催化剂的模板合成，具有大量可访问的Fe‐Nx活性位，可有效减少氧气

由于其丰富的地球，高的原子利用率和出色的活性，分散在氮掺杂碳（Fe-N-C）上的单个铁原子已成为催化贵金属铂（Pt）催化氧还原反应的诱人替代品（ ORR）。但是，当前的Fe-N-C的ORR活性受到活性Fe-N _x物种的低密度和劣质暴露的严重限制。在这里，展示了一种新颖的锌介导的模板合成策略，该策略用于在分层多孔碳（SA-Fe-NHPC）上构建密集暴露的Fe-N _x部分。在热处理2,6-二氨基吡啶/ ZnFe / SiO _2配合物期间，锌阻止了碳化铁纳米颗粒和SiO _2的形成模板促进了分层孔隙的产生，从而在随后的浸提后大大改善了Fe-N _x部分的可及性。结果，SA-Fe-NHPC电催化剂在0.1 m KOH水溶液中表现出前所未有的高ORR活性，半波电势（E _1/2）为0.93 V ，优于Pt / C催化剂和状态最先进的无贵金属电催化剂。作为锌空气电池中的空气电极，SA-Fe-NHPC表现出266.4 mW cm ^-2的大峰值功率密度和出色的长期稳定性。因此，开发了锌介导的模板合成策略以提高Fe‐N _x的密度和可及性。 物种为高性能ORR电催化剂开辟了一条新途径。