电催化剂
化学工程
碳纤维
材料科学
热解
熔盐
金属
石墨烯
剥脱关节
氧化物
金属有机骨架
无机化学
电化学
纳米技术
电极
化学
吸附
有机化学
复合数
复合材料
冶金
物理化学
工程类
作者
Xiaoqian Zhang,Zhaoyuan Lyu,Shichao Ding,Shiyong Zhao,Guangyu Chen,Yuehe Lin,Jincheng Li
标识
DOI:10.1021/acs.jpcc.3c02841
摘要
Zeolitic imidazolate frameworks (ZIFs) are acknowledged as one of the most perfect precursors to synthesize metal–nitrogen/carbon materials in H2-air and Zn-air fuel cells to boost their cathodic sluggish oxygen reactions. However, abundant atomically dispersed metal–nitrogen sites are useless because of being buried in the derived carbon nanoparticles. Here, a molten-salt-assisted pyrolysis strategy is proposed to prepare two-dimensional porous metal–nitrogen/carbon materials with an attempt to expose metal–nitrogen sites, which involves thermal intercalation/exfoliation and space-confined pyrolysis of layer-structured ZIFs from the molten-salt mixture of KCl/LiCl. Specifically, atomically dispersed Co–N/C porous nanosheets were prepared, showing a high special surface area of 1100 m2 g–1 to host abundant exposed Co–Nx sites. When the Co–N/C electrocatalyst was assembled into a liquid-state Zn-air fuel cell, its peak power density and specific capacity reached up to 239.7 mW cm–2 and 784.9 mAh g–1, respectively, and excellent discharge–charge cycling stability was demonstrated. Furthermore, a Co–N/C-based solid-state Zn-air fuel cell was fabricated, also showing outstanding cell performance, such as a peak power density of 147.2 mW cm–2. This work provides a feasible method to synthesize porous two-dimensional functional carbon materials for electrocatalysis and energy devices.
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