The interaction of carbon monoxide with rhodium on potassium-modified CeO2(111)

SURFACE SCIENCE

卷:652

Article

Mullins, David R.¹ 

[1] Oak Ridge Natl Lab, Div Chem Sci, POB 2008,MS 6201, Oak Ridge, TN 37831 USA

关键词: Cerium oxide;    Soft X-ray photoemission;    Temperature programmed desorption;    Potassium;   

DOI  :  10.1016/j.susc.2016.01.024

来源: Elsevier

【 摘 要 】

The adsorption and reactions of CO adsorbed on Rh particles deposited on K-covered CeO2(111) were studied by temperature programmed desorption and photoelectron spectroscopy. K deposited on CeO2(111) forms a KOx over-layer by extracting O from the ceria and partially reducing some of the Ce4+ to Ce3+. CO does not adsorb on the KOx/CeO2-x(111) surface in the absence of Rh particles. CO adsorbed on Rh/K/CeO2(111) adsorbs molecularly on the Rh at 200 K. As the surface is heated the CO spills-over and reacts with the KOx to form carbonate. The carbonate decomposes at elevated temperature to produce CO and CO2. The carbonate stabilizes the KOX so that K desorbs at a higher temperature than it would in the absence of CO. When the Rh and K deposition are reversed so that K is deposited on both the Rh and the CeO2(111), CO adsorbs as CO2- at 200 K. The CO2- decomposes below 350 K to produce gas phase CO and adsorbed CO32- and CO. The CO is stabilized by the K on the Rh and desorbs above 540 K. The carbonate decomposes into gas phase CO and CO2. (C) 2016 Elsevier B.V. All rights reserved.

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