Electrocatalytic Activity and Durability of Pt–Ni Nanowires for Oxygen Reduction

Abstract

Oxygen reduction reaction (ORR) is a key reaction in future energy generation devices such as polymer electrolyte fuel cells (PEFCs) and metal–air batteries. To drive the ORR in PEFCs, Pt–M alloy nanoparticles (M = Ni) on carbon supports have been used as catalysts. Under electrocatalytic conditions, these electrocatalysts are known to degrade involving particle detachment, agglomeration and metal dissolution.[1] These phenomena can be suppressed by increase metal/support interactions: using heteroatom-doped carbon supports[2] and/or nanostructured Pt–M alloy catalysts.[3] Herein, we report synthesis, activity and durability of Pt–Ni nanowires (NWs) for the ORR in acidic media. The Pt–Ni NWs showed higher ORR electrocatalytic activity than Pt/C. The Pt–Ni NWs showed almost no activity loss even after 50,000 potential cycles in acidic media. Physicochemical measurements including in situ Pt L3-edge X-ray absorption spectroscopy [4] revealed that the Pt surface oxide formation under potential control was suppressed after potential cycles, relative to the initial state. This finding suggests that potential cycles could induce strong metal/support interactions, resulting in the formation of highly durable NW catalysts.References.[1] N. Hodnik, G. Dehm, K.J.J. Mayrhofer, Acc. Chem. Res., 49, 2015–2022 (2016).[2] M. Kato, K. Ogura, S. Nakagawa, S. Tokuda, K. Takahashi, T. Nakamura, I. Yagi, ACS Omega, 3, 9052–9059 (2018).[3] J. Li et al., Science, 354, 1414–1417 (2016).[4] K. Nagasawa et al., J. Am. Chem. Soc., 137, 12856 (2015).Acknowledgements.This work was supported by NEDO.