Abstract The development of highly active, inexpensive, and stable bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalysts to replace noble metal Pt and RuO2 catalysts remains a considerable challenge for highly demanded reversible fuel cells and metal-air batteries. Herein, a novel nitrogen doped carbon nanocage (N–CNC-900) is fabricated via facile carbonization of bimetal-organic framework (BMOF). The newly obtained N–CNC-900 catalyst is featured by multiple carbon layers with a wide lattice spacing of 0.434 nm and the aperture of approximate 10 nm, ultrahigh specific surface area and abundant N doping amount as well. As results, the optimized N–CNC-900 exhibits a low overpotential of 1.52 V toward OER at a current density of 10 mA/cm2, and also show a large half-wave potential of 0.90 V for ORR, respectively. High activity and stability toward the bifunctional oxygen electrocatalysis are also demonstrated on the N–CNC-900. When explored as air cathode for rechargeable Zn-air battery, a high open-circuit voltage (1.54 V) and long-term stability (after cycling 200 h) can be realized, outperforming the commercial Pt/C + RuO2 association. This outstanding performance can be attributed to improved reaction kinetics of both ORR and OER, which originates from the enlarged lattice spacing in the few-layer conductive carbon nanocage structure and the existing metal-nitrogen-carbon (M-Nx-C). These results forebode the optimized N–CNC-900 presenting a promising application in metal-air batteries, as well the lattice modulation of carbon materials providing a novel approach for designing advanced electrocatalysts.

中文翻译：

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N掺杂碳纳米笼作为可充电锌空气电池的高性能双功能电催化剂的结构调控

摘要 开发高活性、廉价且稳定的双功能氧还原反应 (ORR) 和析氧反应 (OER) 催化剂来替代贵金属 Pt 和 RuO2 催化剂，对于需求量很大的可逆燃料电池和金属-空气电池来说仍然是一个相当大的挑战。在此，通过双金属有机骨架（BMOF）的简单碳化制备了一种新型氮掺杂碳纳米笼（N-CNC-900）。新获得的 N-CNC-900 催化剂具有多个碳层，具有 0.434 nm 的宽晶格间距和约 10 nm 的孔径，超高的比表面积和丰富的 N 掺杂量。结果，优化的 N-CNC-900 在 10 mA/cm2 的电流密度下对 OER 表现出 1.52 V 的低过电位，并且还分别对 ORR 表现出 0.90 V 的大半波电位。N-CNC-900 也证明了对双功能氧电催化的高活性和稳定性。当探索作为可充电锌空气电池的空气阴极时，可以实现高开路电压（1.54 V）和长期稳定性（循环 200 小时后），优于商业 Pt/C + RuO2 组合。这种出色的性能可归因于 ORR 和 OER 的反应动力学得到改善，这源于几层导电碳纳米笼结构中晶格间距的扩大和现有的金属-氮-碳（M-Nx-C）。这些结果预示着优化的 N-CNC-900 在金属-空气电池中具有广阔的应用前景，碳材料的晶格调制为设计先进的电催化剂提供了一种新方法。