Adsorbate-Induced Structural Changes in 1鈥? nm Platinum Nanoparticles

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• 作者：Yu Lei ; Haiyan Zhao ; Rosa Diaz Rivas ; Sungsik Lee ; Bin Liu ; Junling Lu ; Eric Stach ; Randall E. Winans ; Karena W. Chapman ; Jeffrey P. Greeley ; Jeffrey T. Miller ; Peter J. Chupas ; Jeffrey W. Elam
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：July 2, 2014
• 年：2014
• 卷：136
• 期：26
• 页码：9320-9326
• 全文大小：440K
• ISSN：1520-5126

文摘

We investigated changes in the Pt鈥揚t bond distance, particle size, crystallinity, and coordination of Pt nanoparticles as a function of particle size (1鈥? nm) and adsorbate (H₂, CO) using synchrotron radiation pair distribution function (PDF) and X-ray absorption spectroscopy (XAS) measurements. The 1 nm Pt nanoparticles showed a Pt鈥揚t bond distance contraction of 1.4%. The adsorption of H₂ and CO at room temperature relaxed the Pt鈥揚t bond distance contraction to a value close to that of bulk fcc Pt. The adsorption of H₂ improved the crystallinity of the small Pt nanoparticles. However, CO adsorption generated a more disordered fcc structure for the 1鈥? nm Pt nanoparticles compared to the H₂ adsorption Pt nanoparticles. In situ XANES measurements revealed that this disorder results from the electron back-donation of the Pt nanoparticles to CO, leading to a higher degree of rehybridization of the metal orbitals in the Pt-adsorbate system.