Abstract Metal-free nitrogen-doped carbon materials with advanced porous structure are considered as one of the most promising next-generation non-platinum catalysts for the oxygen reduction reaction (ORR) applied to fuel cells and metal-air batteries. In this work, we develop nitrogen-doped porous carbons based on pyrolysis of pomelo peel by chemical treatment under hypersaline environments containing saturated NaCl, ZnCl2 and FeCl3. The obtained carbon exhibits outstanding ORR activity with a half-wave potential (0.86V vs RHE) and the kinetics current (10.40 mA·cm−2), which are much higher than those obtained from the Pt/C (0.83V, 5.22 mA·cm−2 respectively). Also, the carbon displays superior stability and methanol tolerance to the Pt/C. The significantly improved performance of the synthesized carbon can be attributed to a synergy of enlarged pore volume, increased pyridinic nitrogen doping level and decreased stacking defects of graphite layers in the carbon, caused by the unique hypersaline treatment on the pomelo peel. Moreover, the effect of the hypersaline treatment on the formation of the advanced porous nitrogen-doped carbons is discussed here. The proposed synthetic strategy may offer a facile and efficient route to prepare cost-effective carbon materials derived from other biomasses for the current energy storage and conversion fields.

中文翻译：

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高盐环境氧还原反应处理柚皮的无金属氮掺杂多孔碳

摘要 具有先进多孔结构的无金属氮掺杂碳材料被认为是最有前途的下一代非铂催化剂之一，用于燃料电池和金属空气电池的氧还原反应（ORR）。在这项工作中，我们开发了基于柚皮热解的氮掺杂多孔碳，在含有饱和 NaCl、ZnCl2 和 FeCl3 的高盐环境下通过化学处理。获得的碳表现出优异的 ORR 活性，具有半波电位（0.86V vs RHE）和动力学电流（10.40 mA·cm-2），远高于从 Pt/C 获得的那些（0.83V, 5.22 mA ·cm-2）。此外，碳对 Pt/C 显示出优异的稳定性和甲醇耐受性。合成碳的显着改善的性能可归因于扩大的孔体积、增加的吡啶氮掺杂水平和减少碳中石墨层堆叠缺陷的协同作用，这是由柚皮上独特的超盐处理引起的。此外，这里讨论了超盐处理对高级多孔氮掺杂碳形成的影响。所提出的合成策略可以提供一种简便有效的途径，为当前的能源存储和转换领域制备源自其他生物质的具有成本效益的碳材料。这里讨论了超盐处理对高级多孔氮掺杂碳形成的影响。所提出的合成策略可以提供一种简便有效的途径，为当前的能源存储和转换领域制备源自其他生物质的具有成本效益的碳材料。这里讨论了超盐处理对高级多孔氮掺杂碳形成的影响。所提出的合成策略可以提供一种简便有效的途径，为当前的能源存储和转换领域制备源自其他生物质的具有成本效益的碳材料。