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Graphene-wrapped nitrogen-doped hollow carbon spheres for high-activity oxygen electroreduction†
Materials Chemistry Frontiers ( IF 6.0 ) Pub Date : 2018-05-28 00:00:00 , DOI: 10.1039/c8qm00160j
Ruguang Ma 1, 2, 3, 4, 5 , Ruohao Xing 1, 2, 3, 4, 5 , Gaoxin Lin 1, 2, 3, 4, 5 , Yao Zhou 1, 2, 3, 4, 5 , Qian Liu 1, 2, 3, 4, 5 , Minghui Yang 3, 5, 6, 7 , Chun Hu 1, 2, 3, 4, 5 , Kang Yan 5, 8, 9, 10, 11 , Jiacheng Wang 1, 2, 3, 4, 5
Affiliation  

Graphene wrapping could be used to improve the electrochemical performance of electrodes via the formation of an effective “plane-to-point” conductive network to promote fast electron transfer to the active sites. In this paper, a series of N-doped hollow carbon spheres wrapped by flexible graphene nanosheets (NGCs) have been successfully prepared by the self-assembly of graphene oxide nanosheets onto the surface of hollow polymer spheres, followed by pyrolysis in flowing ammonia. The as-synthesized NGCs show unique hierarchical nanostructures, large hollow cores, large surface areas, and high relative contents of pyridinic and graphitic N groups, as well as uniform wrapping of graphene layers outside of the carbon spheres. The metal-free NGCs show much better activity for the electrocatalytic oxygen reduction reaction with a larger limiting current density and lower onset potential than those without graphene wrapping. They also showed superior long-term stability and fuel crossover effect to commercial Pt/C. These results indicate that graphene wrapping is an effective strategy for improving the activity of electrocatalytic materials via constructing a fast electron transfer network.

中文翻译:

石墨烯包裹的氮掺杂空心碳球,用于高活性氧的电解还原

石墨烯包装可用于提高电极的电化学性能通过有效的“面对点”导电网络的形成,以促进电子快速转移到活性位。在本文中,通过将氧化石墨烯纳米片自组装到空心聚合物球的表面上,然后在流动的氨中热解,已成功制备了由柔性石墨烯纳米片(NGC)包裹的一系列N掺杂空心碳球。合成后的NGC表现出独特的分层纳米结构,大的空心核,大的表面积以及吡啶和石墨N基团的相对含量高,以及石墨烯层在碳球外的均匀包裹。与无石墨烯包裹的NGC相比,无金属的NGC在更大的极限电流密度和更低的起始电势下具有更好的电催化氧还原反应活性。它们还显示出优于商用Pt / C的长期稳定性和燃料穿越效果。这些结果表明石墨烯包裹是提高电催化材料活性的有效策略。通过建立一个快速的电子传输网络。
更新日期:2018-05-28
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