Nitrogen-doped graphene with enhanced oxygen reduction activity produced by pyrolysis of graphene functionalized with imidazole derivatives

作者：Borghei Maryam; Azcune Itxaso; Carrasco Pedro Ma; Sainio Jani; Kauppinen Esko; Ruiz Virginia^*

来源：International Journal of Hydrogen Energy, 2014, 39(24): 12749-12756.

DOI：10.1016/j.ijhydene.2014.06.105

• Nitrogen-doped graphene
• Imidazole-based precursors
• Electrocatalyst
• Oxygen reduction reaction

Nitrogen-doped graphene nanoplatelets (N-GNP) with 1.6-3.3 at.% nitrogen content were synthesized by thermal annealing of GNP functionalized with a series of imidazole-based nitrogen-containing precursors of different nature, charge and nitrogen content. The imidazole derivatives included one ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4) and two polymers, a neutral one, poly(vinylimidazole) (PVI) and a poly(ionic liquid), poly(3-butyl-1-vinylimidazolium bromide) (PBVIBr). N-GNP showed enhanced electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline media compared to pristine GNP, with the number of electrons transferred in oxygen-saturated KOH at low overpotentials following the trend: 2.5 (pristine GNP) %26lt; 2.9 (N-GNP from PVI-GNP) %26lt; 3.3 (N-GNP from BMIBF4-GNP) %26lt; 3.5 (N-GNP from PBVIBr-GNP). Interestingly, ORR catalytic activity did not correlate with total nitrogen content but was more affected by Brunauer-Emmett-Teller (BET) surface area. The most active materials were N-GNP with lowest doping levels and highest surface area resulting from the ionic (imidazolium-based) nitrogen precursors.

• 出版日期2014-8-13