Abstract The sluggish kinetics of oxygen reduction reaction (ORR) seriously restrains the practical implementation of fuel cells and metal-air batteries (MABs). While, Pt-based catalysts are well proven to be effective for the ORR process, they are rather expensive. Therefore, it is critical to developing low-cost and advanced catalysts with a rationally designed structure and abundant reactive sites as alternatives for Pt-based catalysts. Herein, nitrogen-doped hollow carbon polyhedrons (NHCP) have been fabricated by directly pyrolyzing ZIF-8, templated by NaCl. Benefiting from their hollow porous structure, large surface area, high graphitization degree and desired nitrogen bonding type, the as-synthesized NHCP exhibits exceptional ORR electrocatalytic activity with a half-wave potential (E1/2) of 0.86 V, high selectivity and outstanding long-term stability, exceeding most reported nitrogen-doped metal-free carbon electrocatalysts. Furthermore, the assembled Zn-air battery with NHCP cathode delivers a peak power density of 272 mW cm−2, a specific capacity of 740 mAh g−1 and an operation period of 160 h. This contribution provides a new avenue for designing high-performance electrocatalysts for ORR.

中文翻译：

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由盐包封的 ZIF-8 衍生的氮掺杂中空碳多面体，用于高效的氧还原反应

摘要 氧还原反应（ORR）缓慢的动力学严重制约了燃料电池和金属空气电池（MABs）的实际应用。虽然 Pt 基催化剂已被充分证明对 ORR 过程有效，但它们相当昂贵。因此，开发具有合理设计的结构和丰富的反应位点的低成本、先进的催化剂作为 Pt 基催化剂的替代品至关重要。在此，通过直接热解由 NaCl 模板化的 ZIF-8 制备了掺氮中空碳多面体 (NHCP)。得益于其中空多孔结构、大表面积、高石墨化程度和所需的氮键类型，所合成的 NHCP 表现出优异的 ORR 电催化活性，半波电位 (E1/2) 为 0.86 V，高选择性和出色的长期稳定性，超过了大多数报道的氮掺杂无金属碳电催化剂。此外，组装好的具有 NHCP 正极的锌空气电池的峰值功率密度为 272 mW cm-2，比容量为 740 mAh g-1，运行时间为 160 h。这一贡献为设计用于 ORR 的高性能电催化剂提供了新途径。