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Sub‐6 nm Fully Ordered L 1 0 ‐Pt–Ni–Co Nanoparticles Enhance Oxygen Reduction via Co Doping Induced Ferromagnetism Enhancement and Optimized Surface Strain
Author(s) -
Wang Tanyuan,
Liang Jiashun,
Zhao Zhonglong,
Li Shenzhou,
Lu Gang,
Xia Zhengcai,
Wang Chao,
Luo Jiahuan,
Han Jiantao,
Ma Cheng,
Huang Yunhui,
Li Qing
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201803771
Subject(s) - materials science , electrocatalyst , reversible hydrogen electrode , catalysis , bifunctional , nanoparticle , coercivity , chemical engineering , alloy , nanotechnology , electrochemistry , chemistry , electrode , metallurgy , working electrode , biochemistry , physics , condensed matter physics , engineering
Engineering the crystal structure of Pt–M (M = transition metal) nanoalloys to chemically ordered ones has drawn increasing attention in oxygen reduction reaction (ORR) electrocatalysis due to their high resistance against M etching in acid. Although Pt–Ni alloy nanoparticles (NPs) have demonstrated respectable initial ORR activity in acid, their stability remains a big challenge due to the fast etching of Ni. In this work, sub‐6 nm monodisperse chemically ordered L 1 0 ‐Pt–Ni–Co NPs are synthesized for the first time by employing a bifunctional core/shell Pt/NiCoO x precursor, which could provide abundant O‐vacancies for facilitated Pt/Ni/Co atom diffusion and prevent NP sintering during thermal annealing. Further, Co doping is found to remarkably enhance the ferromagnetism (room temperature coercivity reaching 2.1 kOe) and the consequent chemical ordering of L 1 0 ‐Pt–Ni NPs. As a result, the best‐performing carbon supported L 1 0 ‐PtNi 0.8 Co 0.2 catalyst reveals a half‐wave potential ( E 1/2 ) of 0.951 V versus reversible hydrogen electrode in 0.1 m HClO 4 with 23‐times enhancement in mass activity over the commercial Pt/C catalyst along with much improved stability. Density functional theory (DFT) calculations suggest that the L 1 0 ‐PtNi 0.8 Co 0.2 core could tune the surface strain of the Pt shell toward optimized Pt–O binding energy and facilitated reaction rate, thereby improving the ORR electrocatalysis.