Mechanical exfoliation of graphite in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) providing graphene nanoplatelets that exhibit enhanced electrocatalysis

JOURNAL OF POWER SOURCES

卷:271

Article

Hayes, William Ignatius¹  Lubarsky, Gennady¹  Li, Meixian²  Papakonstantinou, Pagona¹ 

[1] Univ Ulster, Dept Engn, Newtownabbey BT370QB, North Ireland

[2] Peiking Univ, Dept Analyt Chem, Beijing 100871, Peoples R China

关键词: Nitrogen-doped graphene nanoplatelets;    Grinding;    Pyrolysis;    Electrocatalysis;    Oxygen reduction reaction;    1-Butyl-3-methylimidazolium hexafluorophosphate;   

DOI  :  10.1016/j.jpowsour.2014.06.168

来源: Elsevier

【 摘 要 】

A novel production method for graphene nanoplatelets (GPs) with enhanced electrocatalytic behaviour is presented. GPs show improvement in their oxygen reduction reaction (ORR) catalysis after prolonging the grinding of graphite in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6). Nitrogen doping of the GPs has inferred a further increase in ORR. The ORR onset potential, cathodic current magnitude and electron transfer efficiency have all improved as a direct consequence of increasing the graphite grinding duration from 30 min to 4 h. Atomic force microscopy has confirmed a decrease in the GP diameter and height as the grinding increases. Raman spectroscopy indicates a higher level of defects present after prolonging the graphite grinding in BMIM-PF6, most likely a result of the increased edge plane exposure. This increased edge plane appears to promote a higher level of nitrogen incorporation as the graphite grinding duration increases, as confirmed by X-ray photoelectron spectroscopy analysis. The stability of the cathodic current assessed by chronoamperometry analysis is higher for the GP and nitrogen doped graphene nanoplatelet (N-GP) samples than the platinum on carbon black (Pt/C). This study presents a novel process for the production of nitrogen doped graphene nanoplatelets, constituting a strategy for the up-scaled production of electrocatalysts. (C) 2014 Elsevier B.V. All rights reserved.

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