Nitrogen-modified carbon-based catalysts for oxygen reduction reaction in polymer electrolyte membrane fuel cells

• Published in: Journal of power sources 2009-03, Vol.188 (1), p.38-44
• Main Authors: Subramanian, Nalini P., Li, Xuguang, Nallathambi, Vijayadurda, Kumaraguru, Swaminatha P., Colon-Mercado, Hector, Wu, Gang, Lee, Jong-Won, Popov, Branko N.
• Format: Article
• Language: English
• Subjects: Applied sciences; Bonding; Carbon-based catalyst; Catalysis; Catalysts; Electrolytes; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Heat treatment; Hydrogen peroxide; Nitrogen modification; Oxygen reduction; PEM fuel cell; Reduction; Reduction (electrolytic)
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2008.11.087

Nitrogen-modified carbon-based catalysts for oxygen reduction were synthesized by modifying carbon black with nitrogen-containing organic precursors. The electrocatalytic properties of catalysts were studied as a function of surface pre-treatments, nitrogen and oxygen concentrations, and heat-treatment temperatures. On the optimum catalyst, the onset potential for oxygen reduction is approximately 0.76 V (NHE) and the amount of hydrogen peroxide produced at 0.5 V (NHE) is approximately 3% under our experimental conditions. The characterization studies indicated that pyridinic and graphitic (quaternary) nitrogens may act as active sites of catalysts for oxygen reduction reaction. In particular, pyridinic nitrogen, which possesses one lone pair of electrons in addition to the one electron donated to the conjugated π bond, facilitates the reductive oxygen adsorption.