Since the first report of Pt monolayer core-shell catalysts by Adzic’s group(1), attractive owing to both their high Pt utilization and ECSAs, numerous efforts have been devoted to the development of these electrocatalysts for fuel cell applications(2-6). Although many varieties of core-shell catalysts have demonstrated improved activity and durability under RDE conditions, reports on the MEA-level tests are still limited(4). Moreover, since a majority of the reported core materials include significant precious metals (e.g. Pd, Au, etc.), the overall cost of the catalysts remains an ongoing concern. Further, the stability of non-precious metal components (Ni, Co, etc.) in the core still presents severe challenges precluding widespread adoption. To address these concerns, various efforts has been devoted to develop durable electrocatalysts with low or non-PGM cores. Nitridation of the core materials is one promising approach to realizing low cost, durable catalysts. Transition metal nitride cores have exhibited enhanced durability for the oxygen reduction reaction at the RDE level(6, 7). Here we report the development of metal nitrides as catalyst cores or support materials and their performance in fuel cell MEAs. Initial results show durability improvements coupled with higher retentions of Pt mass activities and electrochemical surface areas. These results indicate that Pt monolayer catalysts with metal nitride cores or supports are potential candidates for next-generation fuel cell electrocatalysts.

Reference

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