Abstract Controlled doping of specific N species is considered to be an effective yet a challenging strategy to boost the ORR performance of the N-doped carbon. Herein, we report a facile synthesis of tailored active-N-dominated doped defective carbon nanotube (CNT) catalysts by in-situ pyrolysis of defective CNT (OCNT) coated with cobalt(II) ions in ammonia atmosphere. With the guidance of defects and cobalt(II) ions, more active N species (pyridinic-N, graphitic-N and Co-Nx) related to ORR activity are inductively doped into the OCNT forming the active-N-dominated doped OCNT-N catalyst. The resulting OCNT-N shows more favorable ORR activity with an onset potential of 0.94 V vs. RHE, half-wave potential of 0.82 V vs. RHE and better selectivity toward four electron path of ORR due to the synergistic effect of these active nitrogen species and structural defects. Most encouragingly, the according Zn-air batteries using OCNT-N as cathode catalysts can achieve a peak power density of 170.2 mW cm−2 and show a slight voltage loss of only 0.86% after continuous discharge for 12 h at 10 mA cm−2. Our findings demonstrate that the resulting synergy of active N species induced by defects and cobalt(II) ions and defect sites considerably may contribute to boost ORR catalytic activity.

中文翻译：

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用可定制的活性 N 主导的掺杂缺陷 CNT 促进氧还原催化

摘要 特定 N 物种的受控掺杂被认为是提高 N 掺杂碳的 ORR 性能的有效且具有挑战性的策略。在此，我们报告了通过在氨气氛中对涂覆有钴 (II) 离子的缺陷碳纳米管 (OCNT) 进行原位热解，轻松合成了定制的活性 N 主导的掺杂缺陷碳纳米管 (CNT) 催化剂。在缺陷和钴（II）离子的引导下，更多与 ORR 活性相关的活性 N 物质（吡啶-N、石墨-N 和 Co-Nx）被感应掺杂到 OCNT 中，形成活性-N 主导的掺杂 OCNT-N催化剂。所得 OCNT-N 显示出更有利的 ORR 活性，起始电位为 0.94 V 与 RHE，半波电位为 0.82 V 与 RHE。由于这些活性氮物质和结构缺陷的协同作用，RHE 和对 ORR 的四个电子路径具有更好的选择性。最令人鼓舞的是，使用 OCNT-N 作为阴极催化剂的锌空气电池可以达到 170.2 mW cm-2 的峰值功率密度，并且在 10 mA cm-2 下连续放电 12 小时后显示出仅 0.86% 的轻微电压损失. 我们的研究结果表明，由缺陷和钴（II）离子和缺陷位点诱导的活性 N 物质的协同作用可能有助于提高 ORR 催化活性。