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Site blocking and CO/sulfur site exchange processes on stepped Pt surfaces

Streber R, Papp C, Lorenz MPA, Bayer A, Wickert S, Schöppke M, Denecke R, Steinrück HP (2009)

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Publication Type: Journal article

Publication year: 2009

Journal

Original Authors: Streber R., Papp C., Lorenz M.P.A., Bayer A., Wickert S., Schoppke M., Denecke R., Steinrück H.-P.

Publisher: Institute of Physics: Hybrid Open Access

Book Volume: 21

Pages Range: 134018 1-13

Article Number: 134018

Journal Issue: 13

DOI: 10.1088/0953-8984/21/13/134018

Abstract

The influence of preadsorbed sulfur on the adsorption of CO on Pt(355) and Pt(322) is investigated systematically for sulfur precoverages between 0.02 and 0.30ML by insitu x-ray photoelectron spectroscopy of the C 1s and S 2p core levels. The two surfaces have the same nominal terrace width of 5 atomic rows, but different step orientation. For both, at low temperatures (130 and 150K), S preferentially adsorbs at the steps and passivates them for COadsorption. The required S precoverage is significantly smaller for Pt(322), because of the lower number of steps as a result of the S-induced double-step formation. Upon heating, population of step sites with CO occurs due to irreversible CO/S site exchange. At low S precoverages, the characteristic transition temperatures of 165K for Pt(355) and 245K for Pt(322) are significantly different, indicating a higher activation barrier for the CO/S site exchange process for Pt(322). For medium to high S precoverages the transition temperature stays unchanged for Pt(322) but increases for Pt(355). The observed behavior is attributed to a kinetic passivation of the steps by sulfur at low temperatures, which is lifted upon heating. © 2009 IOP Publishing Ltd.

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APA:

Streber, R., Papp, C., Lorenz, M.P.A., Bayer, A., Wickert, S., Schöppke, M.,... Steinrück, H.-P. (2009). Site blocking and CO/sulfur site exchange processes on stepped Pt surfaces. Journal of Physics: Condensed Matter, 21(13), 134018 1-13. https://dx.doi.org/10.1088/0953-8984/21/13/134018

MLA:

Streber, Regine, et al. "Site blocking and CO/sulfur site exchange processes on stepped Pt surfaces." Journal of Physics: Condensed Matter 21.13 (2009): 134018 1-13.

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