The development of high-performance and low-cost oxygen reduction and evolution catalysts that can be easily integrated into existing devices is crucial for the wide deployment of energy storage systems that utilize O2-H2O chemistries, such as regenerative fuel cells and metal-air batteries. Herein, we report an NH3-activated N-doped hierarchical carbon (NHC) catalyst synthesized via a scalable route, and demonstrate its device integration. The NHC catalyst exhibited good performance for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), as demonstrated by means of electrochemical studies and evaluation when integrated into the oxygen electrode of a regenerative fuel cell. The activities observed for both the ORR and the OER were comparable to those achieved by state-of-the-art Pt and Ir catalysts in alkaline environments. We have further identified the critical role of carbon defects as active sites for electrochemical activity through density functional theory calculations and high-resolution TEM visualization. This work highlights the potential of NHC to replace commercial precious metals in regenerative fuel cells and possibly metal-air batteries for cost-effective storage of intermittent renewable energy. [Figure not available: see fulltext.]
Bibliographical noteFunding Information:
This work was supported by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences under Award Number DE-SC0008685. We gratefully acknowledge support from the U.S. Department of Energy, Office of Sciences, Office of Basic Energy Sciences, to the SUNCAT Center for Interface Science and Catalysis. J. W. D. N. acknowledges funding from Agency of Science, Technology, and Research (A*STAR), Singapore. J. W. F. T. acknowledges support from the Croucher Foundation. Part of this work was performed at the Stanford Nano Shared Facilities (SNSF). K. K. acknowledges support from the Future-Innovative Research Fund (No. 1.160088.01) of Ulsan National Institute of Science & Technology (UNIST).
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Electrical and Electronic Engineering