Highly efficient and low‐cost bifunctional electrocatalysts for oxygen reduction and evolution reactions (ORR/OER) are central to new generation rechargeable metal–air batteries. Herein, hierarchical microspheres assembled by in situ generated Co₄N nanoparticles (Co₄N Nps)‐embedded nitrogen‐doped carbon nanotubes (Co₄N@NCNTs) are constructed by a facile urea acid (UA)‐assisted pyrolysis of zeolitic imidazole framework (ZIF)‐67. In this strategy, the UA sharply decomposes at 440 °C to carbonaceous gases, which facilitate the nucleation of Co₄N Nps for the catalytic growth of the NCNT microspheres structure from the intermediate ZIF‐67 polyhedrons. The as‐prepared Co₄N@NCNTs exhibit high N content, abundant Co₄N active species, high electron conductivity, and large specific area on a hierarchical micro‐mesoporous structure. Therefore, the Co₄N@NCNTs not only exceed Pt/C in terms of ORR half wave potential (0.85 vs 0.83 V) and limiting current density (5.50 vs 5.20 mA cm⁻²), but also manifest comparable OER activity with Ru/C. In the rechargeable zinc–air battery test, the bifunctional Co₄N@NCNTs show excellent performance with high discharge and low charge potentials and relatively stable voltage gap as long as 500 cycles, which greatly outperform those of commercial Pt–Ru/C.

中文翻译：

---

在有机金属骨架衍生的碳复合材料上原位生长Co4N纳米粒子-嵌入式氮掺杂碳纳米管，作为高效的氧还原和放出反应的电催化剂

高效，低成本的双功能氧还原和放出反应（ORR / OER）电催化剂对于新一代可充电金属空气电池至关重要。在此，通过方便的尿酸（UA）辅助沸石咪唑骨架的热解，构建了由原位生成的Co ₄ N纳米颗粒（Co ₄ N Nps）嵌入的氮掺杂碳纳米管（Co ₄ N @ NCNTs）组装而成的分层微球。（ZIF）‐67。在此策略中，UA在440°C时急剧分解为碳质气体，这有助于Co ₄ N Nps的成核，以促进NIF微球结构从ZIF-67中间多面体的催化生长。制备的Co ₄ N @ NCNTs含氮量高，钴含量高。₄ N活性物种，高电子电导率和分层微介孔结构上的大比表面积。因此，Co ₄ N @ NCNTs不仅在ORR半波电势（0.85 vs 0.83 V）和极限电流密度（5.50 vs 5.20 mA cm ^-2）方面超过Pt / C ，而且在Ru /下具有可比的OER活性。 C。在可充电锌空气电池测试中，双功能Co ₄ N @ NCNT表现出出色的性能，具有高放电和低充电电势以及相对稳定的电压间隙（长达500个循环），大大优于商用Pt-Ru / C。