Effect of nitrogen precursors on the electrochemical performance of nitrogen-doped reduced graphene oxide towards oxygen reduction reaction

By Soo, Li Ting; Loh, Kee Shyuan; Mohamad, Abu Bakar; Daud, Wan Ramli Wan; Wong, Wai Yin
Published in Journal of Alloys and Compounds NULL 2016

Abstract

Abstract A series of nitrogen-doped reduced graphene oxides (NGs) with different ratios are synthesized by thermal annealing of graphene oxide with melamine or urea. The total nitrogen content in {NG} is high, with values of up to 5.88 at.%. The {NG} samples prepared by melamine exhibited thin transparent graphene sheets structure, with consist of higher nitrogen doping level and quaternary N content compared to those {NG} samples prepared from urea. Electrochemical characterizations show that {NG} is a promising metal-free electrocatalyst for an oxygen reduction reaction (ORR). Incorporation of nitrogen atoms into graphene basal plane can enhances its electrocatalytic activity toward {ORR} in alkaline media. The onset potential and mean number of electron transfers on {NG} 1 are ?0.10 V and 3.80 respectively, which is higher than that of reduced graphene oxide (?0.15 V, 3.52). This study suggests that quaternary-N of the {NG} samples is the active site which determines the {ORR} activity Moreover, the {NG} samples with the transparent layer of graphene-like structure have better {ORR} performances than that of bulk graphite-like {NG} samples.

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