Vc. Belessi et al., Methane combustion on La-Sr-Ce-Fe-O mixed oxides: bifunctional synergisticaction of SrFeO3-x and CeOx phases, APP CATAL B, 31(3), 2001, pp. 183-194
Citations number
48
Categorie Soggetti
Physical Chemistry/Chemical Physics","Environmental Engineering & Energy
The catalytic deep oxidation of methane over perovskite-type mixed oxide ca
talysts is examined. Three groups of mixed oxides (i) La1-yCeyFeO3 (0.0 < y
less than or equal to 0.5), (ii) La1-xSrxFeO3 (0.01 < x less than or equal
to 0.5) and (iii) La1-x-ySrxCeyFeO3 (0.0 < x, y less than or equal to 0.3)
, containing La, Sr, Ce, Fe cations in various ratios were prepared and cha
racterized by XRD, Mossbauer spectroscopy and O-2-TPD measurements. The cat
alysts are active in the temperature range of 440-740 degreesC. A maximum o
f activity appears for y = 0.3, in the series La1-yCeyFeO3 in a wide temper
ature range. The increase of Sr content in the series La1-xSrxFeO3 results
in the enhancement of the reaction rates which is related to the presence o
f SrFeO3-x crystal phase that favors the surface reaction. The double subst
ituted solids La1-x-ySrxCeyFeO3 show higher catalytic activity as compared
to the activity of the two other examined perovskitic series which is relat
ed to the bifunctional synergistic action of CeO2 and SrFeO3-x crystal phas
es in the solids. (C) 2001 Elsevier Science B.V. All rights reserved.