A Facile and Versatile Electrochemical Tuning of Graphene for Oxygen Reduction Reaction in Acidic, Neutral and Alkali media

The need for the development of metal‐free electrocatalysts for oxygen reduction reaction (ORR) has become a necessity to circumvent the prohibitive cost of Pt and the shortcomings of Pt‐based catalysts. Herein, for the first time, graphene surface was tuned by a simple, room temperature, and easily adaptable electrochemical approach using ammonium carbamate as a nitrogen precursor. This method efficiently tuned the graphene surface by incorporating nitrogen and nitrogen functionalities with an unprecedented content of nitrogen (22.48%). The surface tuned graphene (N−Gr) acts as an efficient metal‐free electrocatalyst towards oxygen reduction reaction in a wide pH range, i. e. from neutral (pH 7) to alkaline (pH 14). Also, the N−Gr exhibits a similar Tafel slope (76 mV/dec) to that of Pt/C (64 mV/dec) in 0.1 M KOH. Long term stability and better tolerance to fuel are the other advantages of the N−Gr. The observed ORR activity of the N−Gr might be due to the higher content of nitrogen which provides higher active sites to promote electron transfer in ORR. All these confirm that the surface tuned graphene can be a suitable electrocatalyst for fuel cell applications and the electrochemical approach may pave a way to develop a set of novel and efficient electrocatalysts using the other graphitic nanocarbons.