3D Nitrogen-doped graphene prepared by pyrolysis of graphene oxide with polypyrrole for electrocatalysis of oxygen reduction reaction
3D Nitrogen-doped graphene prepared by pyrolysis of graphene oxide with polypyrrole for electrocatalysis of oxygen reduction reaction
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DOI：
10.1016/j.nanoen.2012.09.002
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发表时间：
2013-03-01
期刊：
影响因子：
17.6
通讯作者：
Wong, Ching-ping
中科院分区：
文献类型：
--
作者：
Lin, Ziyin;Waller, Gordon H.;Wong, Ching-ping
氮掺杂石墨烯（NG）是燃料电池和金属空气电池中氧还原反应（ORR）的一种很有前途的无金属催化剂。然而，它的实际应用取决于通过使用新的合成方法显着降低成本，并通过增加催化活性中心的密度进一步提高催化活性。在这里，我们报告了一种低成本，可扩展的，通过热解氧化石墨烯与合理选择的N源聚吡咯制备NG的合成方法。由于吡咯环中含有大量的氮原子，聚吡咯可以促进石墨态氮的形成，这被认为是高催化活性的关键。所得NG的3D多孔结构具有2- 3at%的N掺杂水平，其中高达44%是石墨N。电化学表征表明，NG具有高的催化活性，通过一个有利的四电子路径形成水，导致高性能和低极化损失的碱性电解质中的ORR。NG还显示出优异的长期稳定性和抗甲醇渗透性，提供了比商业Pt/C催化剂更上级的性能特征。通过X射线光电子能谱和电化学测试揭示了热解温度对NG结构和性质的影响，为合理优化电催化氧化还原活性提供了重要依据。此外，NG对析氧反应（OER）也表现出很高的催化活性，使其具有潜在的应用前景，作为一个双功能的电催化剂的ORR和OER。(C)2013爱思唯尔有限公司保留所有权利。
Nitrogen-doped graphene (NG) is a promising metal-free catalyst for oxygen reduction reaction (ORR) in fuel cells and metal-air batteries. However, its practical application hinges on significant cost reduction by using novel synthetic methods and further improvement of the catalytic activity by increasing the density of catalytically active site. Here we report a low-cost, scalable, synthetic method for preparation of NG via pyrolysis of graphene oxide with a rationally selected N source polypyrrole. Because of the large number of N atoms in pyrrole ring, polypyrrole can facilitate the formation of graphitic N, which is considered vital for high catalytic activity. The resulting 3D porous structure of NG has an N doping level of 2-3 at%, of which as high as 44% are graphitic N. Electrochemical characterizations show that NG has high catalytic activity toward ORR in an alkaline electrolyte via a favorable four-electron pathway for the formation of water, leading to high performance and low polarization loss. The NG also displays excellent long-term stability and resistance to methanol crossover, offering performance characteristics superior to those of a commercial Pt/C catalyst. The effect of pyrolysis temperature on the structure and property of NG are revealed using X-ray photoelectron spectroscopy and electrochemical measurements, providing important insights into the rational optimization of electrocatalytic activity for ORR. In addition, the NG also shows high catalytic activity toward oxygen evolution reaction (OER), rendering its potential application as a bifunctional electrocatalyst for both ORR and OER. (C) 2013 Elsevier Ltd. All rights reserved.