Anomalous diffusion during isopropanol decomposition on (ZrO(2))(1-x) (CeO(2))(x) catalysts

dc.contributor.authorIosifidis, A.en
dc.contributor.authorPetrakis, D. E.en
dc.contributor.authorPomonis, P. J.en
dc.date.accessioned2015-11-24T16:50:17Z
dc.date.available2015-11-24T16:50:17Z
dc.identifier.issn0926-860X-
dc.identifier.urihttps://olympias.lib.uoi.gr/jspui/handle/123456789/9588
dc.rightsDefault Licence-
dc.subjectanomalous diffusionen
dc.subject(zro(2))(1-x)(ceo(2))(x) catalystsen
dc.subjectisopropanol decompositionen
dc.subjectactivation energyen
dc.subjectfractal surface-roughnessen
dc.subjectrenormalization analysisen
dc.subjectmixed oxidesen
dc.subjecttransporten
dc.subjectmediaen
dc.subjectkineticsen
dc.subjectporeen
dc.subjectelectronegativityen
dc.subjectoxidationen
dc.subjectzeolitesen
dc.titleAnomalous diffusion during isopropanol decomposition on (ZrO(2))(1-x) (CeO(2))(x) catalystsen
heal.abstractIn this work the effect of composition of (ZrO(2))(1-x)(CeO(2))(x) catalysts on the ratio gamma = E(c)/E(d) between the activation energies for the isopropanol decomposition, estimated in the chemical reaction (E(c)) and the diffusion (E(d)) controlled regimes, was studied. The solid catalysts with x = 0.0; 0.2: 0.5: 0.8 and 1.0 were prepared by heating the precursors at 400, 600 and 800 degrees C and characterized by N(2) porosimetry, X-ray diffraction, SEM/EDS analysis and NH(3)/TPD. Their catalytic activity for the decomposition of isopropanol in the temperature range 200-400 degrees C was probed in a tubular flow reactor. The estimated Arrhenius plots showed a distinct and well-defined change of slopes corresponding to alternation from the chemical to the internal diffusion-controlled regime of the process. The ratio gamma=E(c)/E(d) of the corresponding activation energies was found equal to gamma approximate to 1 for x = 0.0, meaning total lack of diffusion limitations, and converges to gamma approximate to 2 for x = 1.0, corresponding to classical internal diffusion control. For 0 < x < 1 the values of 1 < gamma < 2 signify anomalous diffusion related linearly to some compositional property of the (ZrO(2))(1-x)(CeO(2)), catalysts. The origin of this phenomenon is discussed in relation to the variable binding strength and friction of movement of the isopropanol species on the more active ZrO(2) and the less active CeO(2) nanoparticles of the solid catalysts. (C) 2009 Elsevier B.V. All rights reserved.en
heal.accesscampus-
heal.fullTextAvailabilityTRUE-
heal.identifier.primaryDOI 10.1016/j.apcata.2009.05.053-
heal.identifier.secondary<Go to ISI>://000268512500027-
heal.identifier.secondaryhttp://ac.els-cdn.com/S0926860X09004098/1-s2.0-S0926860X09004098-main.pdf?_tid=ed698438f781f6eb83764a48fb1d35fb&acdnat=1333035509_f62cee72298fae6a2a8e61160826d578-
heal.journalNameApplied Catalysis a-Generalen
heal.journalTypepeer reviewed-
heal.languageen-
heal.publicationDate2009-
heal.publisherElsevieren
heal.recordProviderΠανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείαςel
heal.typejournalArticle-
heal.type.elΆρθρο Περιοδικούel
heal.type.enJournal articleen

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