Electrochemical water oxidation is a dynamic and basal approach for several energy conversion technologies such as solar fuels and metal–air batteries. Herein, we report a novel ‘nitrogen’ (N) enriched interconnected graphene quantum dots (C-GQDs) as efficient oxygen evolution electrocatalyst, a potential candidate to replace the noble metal OER electrocatalysts. Interestingly, C-GQDs deliver a current density of 10 mAcm-2 at 350 mV, a small Tafel slope of 55 mV/dec and outstanding durability which is much superior to the state-of-the-art precious RuO2. More precisely, the unexpected behaviour of graphene quantum dots towards oxygen evolution reaction (OER) is attributed to the interconnection through N-rich framework (25 %) among the discrete particles. Predominantly, in the pyridine N-oxide, N acts as nucleophilic site and pyridinic N develops p- type doping, responsible for enhanced the OER electrocatalytic activity. The co-existence of both pyridinic N and pyridine N-oxide N induces charge redistribution through π-π delocalization to reduce the *OOH thermodynamic energy barrier. We hope that our study will encourage to develop more efficient electrocatalysts with more effective doping or surface functionalized structure by understanding the dopant nature.
Bibliographical noteFunding Information:
Authors thank Dr. M. Kulkarni. S.K and B.M thank Ms. Krati Joshi for her help. SK thanks IUSSTF (22-2012/2013-14), its members Prof. P. M. Ajayan and Prof. S. Talapatra. Authors thank CSC-0101 for funding. Authors thank all the CIF staffs, CSIR-CECRI.
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
- Functionalized Interconnected GQDs (C-GQDs)
- Glassy carbon electrode (GCE)
- Graphene Quantum Dots (GQDs)
- Oxygen evolution reaction (OER)
- Rotating disk electrode (RDE)