Russian Journal of General Chemistry, Vol. 72, No. 1, 2002, pp. 13 16. Translated from Zhurnal Obshchei Khimii, Vol. 72, No. 1, 2002,
pp. 17 20.
Original Russian Text Copyright
2002 by Aleksandrov, Tsyganova, Ivanovskaya, Vorozheikin.
Kinetic Regularities of the Heterogeneous Catalytic Oxidation
of Carbon Monoxide on Ceramic Foam supported Catalysts
Yu. A. Aleksandrov, E. I. Tsyganova, K. E. Ivanovskaya, and I. A. Vorozheikin
Research Institute of Chemistry, Lobachevskii Nizhny Novgorod State University, Nizhny Novgorod, Russia
Received May 22, 2000
Abstract The process of high-temperature formation of synthetic ceramic foam was studied by means of
differential thermal analysis, and kinetic regularities of heterogeneous catalytic oxidation of carbon monoxide
with catalysts supported on various-composition ceramics and promoted with palladium chloride and man-
ganese(II) orthophosphate were studied.
The problem of minimization of the environmental
impact of carbon monoxide has stimulated search
for new catalytic systems for the oxidation of CO
to CO2.
catalytic technique on catalysts supported on the
ceramics and promoted with palladium chloride and
manganese(II) orthophosphate. The denotation of the
catalysts and the conditions of kinetic experiments are
given in the table.
We earlier showed [1] that such catalysts are quite
prospective to support on the synthetic ceramic foam
Figure 1 represents the thermoanalytical curves for
(
hereinafter, ceramics ) produced on the basis of
KhIPEK ceramics (Technical Specifications TU 5759-
10-10657190-97) and featuring high thermal and
ceramics (sample I) and V O on ceramics (sample
2
5
II). As seen, samples I and II in the range 60 170 C
lose water, and the DTG curve show peaks from two
types of associated water (Fig. 1a). In this range,
ceramics undergoes an almost 10% weight loss. An
inconsiderable weight loss up to 525 C was also ob-
served with sample I and up to 689 C with sample II;
therewith, the total weight loss was, according to TG
data, 20%. On further heating (to 1000 C), the TG
curve no longer changed, implying invariable weight
of the ceramics. The DTA curves for samples I and II
displayed endothermic peaks at 520 and 745 C,
apparently associated with transitions of the hydrates
Al O nH O, constituting the ceramics, from one
0
chemical stabilities [2].
As we noted in [1], the most active are catalysis
supported on vanadium(V) oxide-containing ceramics
and promoted with palladium chloride additives. They
initiated oxidation of CO to CO already at room
2
temperature, and complete conversion was observed
at 200 C.
In the present work we used DTA to elucidate
characteristic features of ceramics formation on termal
treatment of freshly prepared KhIPEK ceramics and
to study kinetic regularities of the heterogeneous
2
3
2
crystal modification to another ( -Al O to -Al O )
2
3
2
3
catalytic oxidation of CO to CO by the pulse micro-
[3]. The DTA curve of sample II also shows an endo-
2
Compositions of catalysts for oxidation of CO to CO , conditions of kinetic experiments, and activation parameters of the
2
process
Catalyst
weight, g
F,
ml/s
E ,
kJ/mol
d,
mm
log kapp
(200 C)
Catalysta
a
No.
T,
C
log A
1
2
3
4
5
1% Pd/(II)
200 320
160 230
153 223
95 320
0.908
1.5391
0.908
1.4907
0.4630
1.25
0.5
1.25
0.71
1.25
74.4 10.8
85.3 2.3
43.4 5.1
41.8 3.2
198.5 14.7
2.42 0.35
4.08 0.16
0.20 0.04
0.68 0.75
12.8 0.97
0.4 0.1
1.0 0.4
0.4 0.1
1.0 0.4
1.0 0.5
5.81
5.36
5.0
5.29
9.76
0.1% Pd(II)/BaSO4
1% Pd(II)/V O
2
5
V O
2
5
Mn(II)
300 400
a
All on ceramics; produced on the basis of KhIPEK ceramics (TU 5759-010-1065-7190-97), modified by Fe(III), P(V), and B(III)
oxides.
1
070-3632/02/7201-0013$27.00 2002 MAIK Nauka/Interperiodica