Mechanistic study of N8- polynitrogen synthesis and its oxygen reduction reaction

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Fuel cells are devices for direct conversion of the chemical energy of a fuel into electricity through electrochemical reactions. However, widespread implementation of fuel cells has been hampered by the high cost of the platinum catalyst. Despite many decades of research, few non-precious metal fuel cell catalysts have been found that can rival the performance and stability of platinum. The project will investigate low-cost alternatives to platinum as fuel cell catalysts, thus helping to achieve higher penetration of fuel cell technology into the energy sector and increasing our Nation's energy security. The project will also include educational and outreach programs that will enhance energy awareness at all educational levels and build a future workforce highly trained in energy technology.The project under Dr. Xianqin Wang from New Jersey Institute of Technology, Newark, NJ, involves exploring polymeric nitrogen (PN) supported on multi-walled carbon nanotubes as the cathode catalyst for potential use in proton exchange membrane (PEM) fuel cells. The project seeks to advance fundamental understanding of PN synthesis and the role of the carbon-supported polymeric nitrogen species to promote the oxygen reduction reaction (ORR). The active sites associated with the anionic polynitrogen species will be linked to enhanced O=O bond reduction and more detailed understanding of the electrochemical reduction mechanism as obtained from both advanced characterization tools and density functional theory (DFT). In particular, the O2 chemisorption mode will be probed under reaction conditions by in situ shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS), which when combined with kinetic experiments and theoretical calculations, can shed deeper insight regarding the ORR mechanism and its relationship to catalyst structure. The results will provide the basis for metal-free, green catalytic materials as oxygen reduction catalysts for hydrogen, methanol, and glucose or biomass powered fuel cells. Successful results from this effort will lead to use of non-metallic polymeric nitrogen in other applications, such as mild and selective oxidation reactions, hydrogenation reactions and multipurpose applications in biomass conversion and sustainable chemistry. Dr. Wang is actively involved in inspiring young students, especially female and underrepresented minorities, to develop their interests in science through research. She will provide opportunities for a diverse group of graduate, undergraduate, and K-12 students to collaborate in this interdisciplinary research project and work with scientists from different fields.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.