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Coating Pt–Ni Octahedra with Ultrathin Pt Shells to Enhance the Durability without Compromising the Activity toward Oxygen Reduction
Author(s) -
Park Jinho,
Liu Jingyue,
Peng HsinChieh,
FigueroaCosme Legna,
Miao Shu,
Choi SangIl,
Bao Shixiong,
Yang Xuan,
Xia Younan
Publication year - 2016
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201600566
Subject(s) - octahedron , catalysis , materials science , cobalt , sulfuric acid , nanocrystal , durability , inorganic chemistry , chemical engineering , crystallography , metallurgy , chemistry , nanotechnology , crystal structure , composite material , organic chemistry , engineering
We describe a new strategy to enhance the catalytic durability of Pt–Ni octahedral nanocrystals in the oxygen reduction reaction (ORR) by conformally depositing an ultrathin Pt shell on the surface. The Pt–Ni octahedra were synthesized according to a protocol reported previously and then employed directly as seeds for the conformal deposition of ultrathin Pt shells by introducing a Pt precursor dropwise at 200 °C. The amount of Pt precursor was adjusted relative to the number of Pt–Ni octahedra involved to obtain Pt–Ni@Pt 1.5L octahedra of 12 nm in edge length for the systematic evaluation of their chemical stability and catalytic durability compared to Pt–Ni octahedra. Specifically, we compared the elemental compositions of the octahedra before and after treatment with acetic and sulfuric acids. We also examined their electrocatalytic stability toward the ORR through an accelerated durability test by using a rotating disk electrode method. Even after treatment with sulfuric acid for 24 h, the Pt–Ni@Pt 1.5L octahedra maintained their original Ni content, whereas 11 % of the Ni was lost from the Pt–Ni octahedra. After 10 000 cycles of ORR, the mass activity of the Pt–Ni octahedra decreased by 75 %, whereas the Pt–Ni@Pt 1.5L octahedra only showed a 25 % reduction.