Fe–Co bimetallic electrocatalysts show tremendous promise for both oxygen reduction reaction (ORR) and oxygen evolution reaction in the alkaline medium to replace precious metal catalysts. Here, we report a successful size modulation strategy for FeCo binary alloys in situ growth on the carbon matrix. Analogous to Pt nanoparticles, the size modulation could give rise to increased active sites in FeCo-based catalysts without altering their chemical properties. The compositionally optimized template with abundant carbon nanotubes and uniform distribution of FeCo alloy nanoparticles, exhibits superior electrocatalytic activity by achieving a high-performance half-wave potential of 0.88 V toward ORR as well as robust stability after 10 000 cycles. The open-circuit potential (Voc) of the liquid Zn–air battery is close to 1.40 V which is comparable with that of the Zn–air battery equipped with Pt/C+IrO₂. Our findings offer new prospects for understanding metal particle sizes and electrocatalytic performance of pyrolyzed transition metal–carbon materials.

Fe-Co双金属电催化剂对于在碱性介质中代替贵金属催化剂的氧还原反应（ORR）和氧释放反应都具有广阔的前景。在这里，我们报告了在碳基体上原位生长FeCo二元合金的成功尺寸调节策略。类似于Pt纳米颗粒，尺寸调节可以在基于FeCo的催化剂中增加活性位，而不会改变其化学性质。具有丰富的碳纳米管和均匀分布的FeCo合金纳米粒子的成分优化模板，通过实现对ORR的0.88 V的高性能半波电势以及在1万次循环后的稳定稳定性，表现出卓越的电催化活性。开路电位（Voc）的液态Zn-空气电池的电压接近1.40 V，这与配备Pt / C + IrO ₂的Zn-空气电池的电压相当。我们的发现为理解热解过渡金属碳材料的金属粒径和电催化性能提供了新的前景。