R. Wagner: CO-Oxidation over Ruthenium Catalysts in a Micro Flow Reactor: Steady State Stoichiometry Programmed Reaction (ssSPR) Measurements
Measurements Dec. 2010 – Mar. 2011; Manuscript 4. Oct. 2014; Reviewed 30. Dec. 2014; Published 15. Oct. 2015
Abstract
The CO oxidation over Ru model catalysts at ambient pressure was studied utilizing the stoichiometry programmed
reaction technique in a micro flow reactor. In these experiments the stoichiometry of the educt flow, described by the
factor .. was tuned from oxidizing to reducing feed and back. By such a routine a clean Ru(0001) surface and a
RuO2(110) film on Ru(0001) as initial states of model catalysts were investigated in-situ in a steady state manner at
453 K ,500 K, 600 K and 700 K. After reaction TPD, LEED and AES measurements were performed quasi-in-situ to
characterize the samples at several reaction stages.
At 600 K and 700 K all samples showed high activity as well as deactivation. This is accompanied by changes of the
composition/morphology of the catalyst and the chemical potential of the educt flux. Very active species were a relatively
smooth RuO2 film ((1x1)-RuO2(110)/Ru(0001) LEED pattern) with an oxygen amount of 18 MLE, and a 0.15 MLE
layer of chemisorbed O on Ru(0001).
Keywords
CO-Oxidation, Deactivation, Ambient Pressure, Ruthenium, Flow Reactor, SPR, Stoichiometry Programmed Reaction
download Surf. Cons. Comm. 1 (2015) 1-18
R. Wagner: Ru-O Catalyst Phases after CO-Oxidation
Measurements Dec. 2010 – Mar. 2011; Manuscript 7. Oct. 2014; Reviewed 9. Jun. 2015; Published 15. Oct. 2015
Abstract
Surfaces of reacted Ru-O catalysts were investigated by means of TPD, AES and LEED. These surfaces were produced
by modification of initially well-defined Ru(0001) and RuO2(110)/Ru(0001) samples by CO oxidation in both stoichiometry
and temperature programmed experiments. We could prove the existence of a variety of known and formerly
unknown oxygen and COx species in adlayers, at 2D or 3D islands or incorporations. We were fascinated to find that
these species occurred either exclusive or coexisting, either at or beneath the catalyst surface.
Keywords
CO-Oxidation, Ruthenium, AES, TPD, LEED
download Surf. Cons. Comm. 1 (2015) 19-36
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