Comparative study of La-Sr-Fe-O perovskite-type oxides prepared by ceramic and surfactant methods over the CH(4) and H(2) lean-deNO(x)
Φόρτωση...
Ημερομηνία
Συγγραφείς
Stathopoulos, V. N.
Belessi, V. C.
Bakas, T. V.
Neophytides, S. G.
Costa, C. N.
Pomonis, P. J.
Efstathiou, A. M.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Elsevier
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Applied Catalysis B-Environmental
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
Mixed oxides of the general formula La(0.8)Sr(0.2)FeO(3-x) were prepared by ceramic and surfactant methods and tested towards the NO/H(2)/O(2) and NO/CH(4)/O(2) lean-deNO(x) reactions in the 200-450 degrees C range. The materials were characterized for their bulk and surface composition by XRD, Mossbauer and XPS techniques. The main crystal phases detected were perovskites LaFeO(3) and SrFeO(3-x), and alpha-Fe(2)O(3). The Mossbauer technique allowed the precise determination of the composition of Fe-containing phases in the solids prepared by both the ceramic and surfactant methods. Significant differences in the composition of the phases and the surface chemical states of Fe, Sr and La were revealed among the two solid compositions. For the CH(4) lean-deNO(x) reaction at 350 degrees C, the La(0.8)Sr(0.2)FeO(3-x) solid composition (LSF-2) prepared by the surfactant method exhibited an increase by 50% in the rate of NO conversion and by 30% in the rate of N(2) formation (per gram basis) as compared to the solid prepared by the ceramic method (LSF-1). An opposite relative catalytic activity behavior was observed for the two solids when tested towards the H(2) lean-deNO(x) reaction. At 375 degrees C (maximum activity observed) the solid prepared by the ceramic method (LSF-1) exhibited an increase by 83% in the rate of N(2) formation as compared to the solid prepared by the surfactant method (LSF-2). It is suggested that the mobility of surface lattice oxygen, the concentration of oxygen vacant sites, and the mixed valences of metal cations present in the La(0.8)Sr(0.2)FeO(3-x) solid all influenced by the preparation method used are the main parameters that largely influenced the catalytic behavior observed over the LSF-1 and LSF-2 solids. (C) 2009 Elsevier B.V. All rights reserved.
Περιγραφή
Λέξεις-κλειδιά
perovskites, no reduction by h(2), no reduction by ch(4), lean-deno(x), selective catalytic-reduction, lean-burn conditions, noble-metal catalysts, de-nox reaction, nitric-oxide, excess oxygen, nitrogen monoxide, low-temperatures, mixed oxides, pt/mgo-ceo2 catalyst
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000272251600001
http://ac.els-cdn.com/S0926337309003506/1-s2.0-S0926337309003506-main.pdf?_tid=3d87bebd84bda90570f731d71c7da06c&acdnat=1333036726_f238ee03371a430e1b32a39041844f88
http://ac.els-cdn.com/S0926337309003506/1-s2.0-S0926337309003506-main.pdf?_tid=3d87bebd84bda90570f731d71c7da06c&acdnat=1333036726_f238ee03371a430e1b32a39041844f88
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας