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Kinetic modeling of CO oxidation over La1-xA x Mn0.6Cu0.4O3 (A = Sr and Ce) nanoperovskite-type mixed oxides
Zonouz, P. R.; Niaei, A. & Tarjomannejad, A.
Abstract
In this paper, catalytic oxidation of CO over the
perovskite-type oxides La1-xA
x
Mn0.6Cu0.4O3 (A = Sr and
Ce, x = 0, 0.1, 0.2, 0.3 and 0.4) was investigated. The
catalysts were synthesized by sol–gel auto-combustion
method and were further characterized by XRD, BET, FTIR,
H2-TPR and SEM. XRD patterns revealed that the
oxides were single-phase perovskite-type oxides. Traces of
Cu2O3, Sr2O3 and Ce2O3 were also detected in perovskites
with high contents of Sr and Ce. Specific surface areas of
perovskites were also determined to be about 16 and
32 m2/g. Reducibility of the perovskites, also, is strongly
affected by substitution of La in A site by Sr and Ce.
Perovskite catalysts show a high activity in catalytic oxidation
of CO; substitution of Sr and Ce further enhanced
CO oxidation activity. Highest activity was achieved by
La0.7Ce0.3Mn0.6Cu0.4O3: Nearly complete elimination of
CO was achieved at 145 °C with this catalyst. Kinetic
studies for CO oxidation were performed based on Langmuir–
Hinshelwood mechanisms. According to kinetic
calculations, the most probable mechanism is the LH–OS–
ND (adsorption of the reagents on same types of sites and
non-dissociative adsorption of oxygen) which can predict
the experimental data with correlation coefficient of
R2 = 0.9933.
Keywords
La1-xAxMn0.6Cu0.4O3; Perovskite; CO oxidation; Kinetic
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