Study on Nucleation and Growth Mechanism of Electrodeposited Pt-Ni Alloy

Abstract

Pt-M (M=Ni, Co, Fe, et.al) alloy nanoparticle catalysts have been proved to be effective oxygen reduction reaction (ORR) catalysts with reduced Pt loading in proton exchange membrane fuel cells (PEMFCs). Electrodeposition methods have shown potential application on large-scale preparation of Pt catalysts by simplifying the synthetic settings as well as high controllability1,2. While their performance is unsatisfied due to the over-large particles and the difficulty of Pt-M co-deposition in aqueous solution. We herein modified the current electrodeposition method by switching aqueous electrolyte to water-soluble N, N-Dimethylformamide (DMF) for electrochemically co-depositing Pt-Ni alloy nanoparticles. Highly monodispersed Pt-Ni alloy nanoparticles are directly deposited on carbon substrate (Pt-Ni/C) via a facile potentiostatic technique from the selected DMF solution system and show promising specific activity towards ORR. Physiochemical characterizations, electrochemical tests and computational evaluations via density functional theory (DFT) were applied to uncover the internals of formation of highly monodispersed nanoparticles as well as the nucleation and growth of Pt-Ni nanoparticles. Our finding provides a hopeful extended Pt-M catalyst layer production strategy for PEMFCs and a new idea for the nucleation and growth mechanism for electrodeposited Pt-M alloy. Keywords: electrodeposition, Pt-Ni alloy nanoparticles, nucleation and growth mechanism, density functional theory Reference [1] A.J. Martín, A.M. Chaparro, M.A. Folgado, B. Gallardo, L. Daza, ECS Transactions, 2008, 13, 13.[2] P. Dhanasekaran, K. Lokesh, P.K. Ojha, A.K. Sahu, S.D. Bhat, D. Kalpana, Journal of Colloid and Interface Science, 2020, 572, 198. Acknowledgements This work was supported in part by National Natural Science Foundation of China (21975157) and the National Key Research and Development Program of China (2016YFB0101201 and 2016YFB0101312). Figure 1