Identical Location Transmission Electron Microscopy Imaging of Site-Selective Pt Nanocatalysts: Electrochemical Activation and Surface Disordering

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• 作者：Rosa M. Ar谩n-Ais ; Yingchao Yu ; Robert Hovden ; Jose Solla-Gull贸n ; Enrique Herrero ; Juan M. Feliu ; H茅ctor D. Abru帽a
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：December 2, 2015
• 年：2015
• 卷：137
• 期：47
• 页码：14992-14998
• 全文大小：526K
• ISSN：1520-5126

文摘

We have employed identical location transmission electron microscopy (IL-TEM) to study changes in the shape and morphology of faceted Pt nanoparticles as a result of electrochemical cycling; a procedure typically employed for activating platinum surfaces. We find that the shape and morphology of the as-prepared hexagonal nanoparticles are rapidly degraded as a result of potential cycling up to +1.3 V. As few as 25 potential cycles are sufficient to cause significant degradation, and after about 500鈥?000 cycles the particles are dramatically degraded. We also see clear evidence of particle migration during potential cycling. These finding suggest that great care must be exercised in the use and study of shaped Pt nanoparticles (and related systems) as electrocatlysts, especially for the oxygen reduction reaction where high positive potentials are typically employed.