Kinetically Controlled Autocatalytic Chemical Process for Bulk Production of Bimetallic Core–Shell Structured Nanoparticles

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• 作者：Fadlilatul Taufany ; Chun-Jern Pan ; John Rick ; Hung-Lung Chou ; Mon-Che Tsai ; Bing-Joe Hwang ; Din-Goa Liu ; Jyh-Fu Lee ; Mau-Tsu Tang ; Yao-Chang Lee ; Ching-Iue Chen
• 刊名：ACS Nano
• 出版年：2011
• 出版时间：December 27, 2011
• 年：2011
• 卷：5
• 期：12
• 页码：9370-9381
• 全文大小：1261K
• 年卷期：0
• ISSN：1936-086X

文摘

Although bimetallic core@shell structured nanoparticles (NPs) are achieving prominence due to their multifunctionalities and exceptional catalytic, magnetic, thermal, and optical properties, the rationale underlying their design remains unclear. Here we report a kinetically controlled autocatalytic chemical process, adaptable for use as a general protocol for the fabrication of bimetallic core@shell structured NPs, in which a sacrificial Cu ultrathin layer is autocatalytically deposited on a dimensionally stable noble-metal core under kinetically controlled conditions, which is then displaced to form an active ultrathin metal-layered shell by redox–transmetalation. Unlike thermodynamically controlled under-potential deposition processes, this general strategy allows for the scaling-up of production of high-quality core–shell structured NPs, without the need for any additional reducing agents and/or electrochemical treatments, some examples being Pd@Pt, Pt@Pd, Ir@Pt, and Ir@Pd. Having immediate and obvious commercial potential, Pd@Pt NPs have been systematically characterized by in situ X-ray absorption, electrochemical-FTIR, transmission electron microscopy, and electrochemical techniques, both during synthesis and subsequently during testing in one particularly important catalytic reaction, namely, the oxygen reduction reaction, which is pivotal in fuel cell operation. It was found that the bimetallic Pd@Pt NPs exhibited a significantly enhanced electrocatalytic activity, with respect to this reaction, in comparison with their monometallic counterparts.