Electrosorption and catalytic properties of bare and Pt modified single crystal and nanostructured Ru surfaces

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• 作者：S.R Brankovic ; J.X Wang ; Y Zhu ; R Sabatini ; J McBreen ; R.R Ad?i? ; ^{adzic@bnl.gov}
• 关键词：Single crystal Ru(0001) and Ru(10&minus ; 10) electrodes ; Ru oxidation ; Pt deposition ; Ru nanoparticles ; CO tolerance
• 刊名：Journal of Electroanalytical Chemistry
• 出版年：2002
• 出版时间：26 July 2002
• 年：2002
• 卷：524-525
• 期：Complete
• 页码：231-241
• 全文大小：469 K

文摘

The electrosorption and catalytic properties of bare and Pt modified Ru(0001) and Ru(10?0) single crystal surfaces and carbon supported Ru nanoparticles have been studied by electrochemical, surface X-ray scattering, scanning tunneling microscopy, Fourier transform infrared spectroscopy and high resolution transmission electron microscopy techniques. The electrochemical surface oxidation of Ru(0001) in H₂SO₄ is an one-electron process resulting in 1 monolayer oxygen uptake and the increased spacing between the top two Ru layers from 2.13 ? at 0.1 V to 2.20 ? at 1.0 V. About 1/3 monolayer of bisulfate anions are coadsorbed with hydronium cations at low potentials. In HClO₄ solution, the adsorption process at ?.1 V is due to the surface oxidation apparently to RuOH rather than to hydrogen adsorption. The oxidation of Ru(10?0) is quite facile and a progressive growth of the oxide layer is observed in repeated potential cycles. Spontaneous deposition of a submonolayer-to-multilayer of Pt on metallic Ru surfaces is a new phenomenon involving a noble metal deposition on a noble metal substrate through a local cell mechanism. The electrocatalysts prepared by spontaneous deposition of Pt on Ru nanoparticles have high activity and high CO tolerance exceeding those of the state-of-the-art commercial catalysts containing several times higher Pt loadings. Electronic effects appear to play a role in providing enhanced CO tolerance of Pt submonolayers on Ru nanoparticles.