Active Non-Precious Metal Based Nitride Catalysts for the Oxygen Reduction Reaction

Abstract

Proton-exchange membrane fuel cells (PEMFC) that convert chemical energy from a fuel into electricity offer a promising route for decarbonisation of both the electricity and transportation sector. Today, platinum-based catalysts are the most active and widely implemented catalyst for both the oxidation and reduction reactions in a PEMFC. However, concerns regarding the scarcity and high costs associated with platinum motivate the search for alternative active and stable catalysts. 1 In particular at the cathode, the sluggish oxygen reduction reaction (ORR) kinetics requires a high loading of platinum. Thus, new non-platinum group metal based catalysts are necessary to reduce the cost of PEMFC technologies. One class of materials that has attracted recent attention for ORR in acidic media are the nitrides. In particular, hexagonal boron nitride ( h -BN), 2 and transition metal nitrides have shown excellent activity and promising stability ORR catalysts. 3 In this work we investigate the ORR activity and stability of non-precious metal nitride catalysts as a function of synthesis technique, morphology and chemical composition. Alloying and doping the nitride catalysts, as well as probing the role of substrate identity are investigated. We compare our electrochemical data with computationally investigated ORR activity using density functional theory (DFT) calculations. References (1) Seh, Z. W.; Kibsgaard, J.; Dickens, C. F.; Chorkendorff, I.; Nørskov, J. K.; Jaramillo, T. F. Science (80-. ). 2017 , 355 (6321), eaad4998. (2) Uosaki, K.; Elumalai, G.; Noguchi, H.; Masuda, T.; Lyalin, A.; Nakayama, A.; Taketsugu, T. 2014 , 136 (111), 6542. (3) Cao, B.; Neuefeind, J. C.; Adzic, R. R.; Khalifah, P. G. Inorg. Chem. 2015 , 54 (5), 2128.