Co-N Decorated Hierarchically Porous Graphene Aerogel for Efficient Oxygen Reduction Reaction in Acid
Co-N Decorated Hierarchically Porous Graphene Aerogel for Efficient Oxygen Reduction Reaction in Acid
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DOI：
10.1021/acsami.5b12746
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发表时间：
2016-03-16
影响因子：
9.5
通讯作者：
Chen, Zhongwei
中科院分区：
文献类型：
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作者：
Fu, Xiaogang;Choi, Ja-Yeon;Chen, Zhongwei
氮功能化石墨烯材料由于其在碱性电解质中具有可观的活性和优异的稳定性，已被证明是一种有前景的氧还原反应（ORR）电催化剂。然而，它们在酸性介质中表现出不可接受的催化活性。在这里，制备了分级多孔 Co-N 功能化石墨烯气凝胶，作为酸性电解质中 ORR 的有效催化剂。在制备过程中，引入聚苯胺（PANI）作为成孔剂，帮助石墨烯自组装成多孔气凝胶网络，并引入氮前体来诱导原位氮掺杂。因此，热处理后有效地形成了具有大表面积（485 m(2) g(-1)）和丰富的介孔/大孔的Co-N装饰石墨烯气凝胶框架。这种高度理想的结构不仅可以为ORR暴露足够的活性位点，而且可以保证催化过程中的快速传质，从而提供显着的催化活性，具有正的起始电位和半波电位、低过氧化氢产率、高抗甲醇渗透性以及在酸性介质中可与商用Pt/C相媲美的稳定性。
Nitrogen-functionalized graphene materials have been demonstrated as promising electrocatalyst for the oxygen reduction reaction (ORR), owning to their respectable activity and,excellent stability in alkaline electrolyte. However, they exhibit unacceptable catalytic activity in acid medium. Here, a hierarchically porous Co-N functionalized graphene aerogel is prepared as an efficient catalyst for the ORR in acid electrolyte. In the preparation process, polyaniline (PANI) is introduced as a pore-forming agent to aid in the self-assembly of graphene species into a porous aerogel networks, and a nitrogen precursor to induce in situ nitrogen doping. Therefore, a Co-N decorated graphene aerogel framework with a large surface area (485 m(2) g(-1)) and an abundance of meso/macropores is effectively formed after heat treatment. Such highly desired structures can not only expose sufficient active sites for the ORR but also guarantee the fast mass transfer in the catalytic process, which provides significant catalytic activity with positive onset and half wave potentials, low hydrogen peroxide yield, high resistance to methanol crossover, and remarkable stability that is comparable to commercial Pt/C in acid medium.