1070-4272/02/7504-0582 $27.00 C 2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 4, 2002, pp. 582!584. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 4, 2002,
Original Russian Text Copyright + 2002 by Subbotin, Vorob’eva, Gudkov, Yakerson, Kustov.
Temperature Hysteresis in CO Oxidation
on Copper Oxide Catalyst Applied to a Steel Gauze
A. N. Subbotin, M. P. Vorob’eva, B. S. Gudkov, V. I. Yakerson, and L. M. Kustov
Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
Received November 21, 2001
Abstract-The temperature hysteresis during the heterogeneous catalysis was studied by an example of model
reaction of CO oxidation on copper oxide catalyst applied to a stainless steel gauze.
Over several years, we have been developing a
concept that the local overheating of active centers is
the main process responsible for the temperature hys-
teresis in heterogeneous catalysis . Such over-
heating is due to impeded removal of heat from the
active centers in the course of exothermic reactions.
Recently, the methods of preparation were pro-
posed and the properties were studied of new hetero-
geneous catalysts based on a metal gauze [4, 5]. These
catalysts, containing supporting and (or) catalytically
active metals immobilized on the surface of stainless
steel gauze, have a number of advantages, of which
the most important is the high heat-exchange coeffi-
cient. This makes such catalysts especially promising
for reactions with a large positive heat effect.
Here we attempted to use such gauze catalysts to
confirm the hypotheses explaining the temerature
hysteresis in terms of the local overheating of active
centers. The test was performed by an example of
the model reaction of carbon monoxide oxidation on
A stainless steel gauze made of a 50-mm-thick wire
was used as metallic support of a catalyst. Prior to
depositing oxide layer, the gauze surface was treated
electrochemically and then by chemical etching.
Two types of catalyst samples were prepared:
(1) a steel gauze to which copper oxide was applied
directly (CuO/gauze) and (2) a stainless steel gauze to
which aluminum oxide and then copper oxide were
The CuO/gauze catalyst was prepared by electro-
chemical deposition of copper from a CuSO
tion with subsequent oxidation. The deposition cur-
rent was 500 mA. Two parallel copper plates were
cathode. The metallic copper was oxidized by calci-
nation in air (flow rate 3 l h
) at 550oC for 4 h.
After calcination, the CuO/gauze sample contained
140 mg CuO.
/gauze catalyst was supported with
a steel gauze preliminarily coated with Al
minum oxide was deposited electrophoretically .
For this purpose, a gauze cathode was plunged into alu-
minum hydroxide sol containing 5.5 g l
The deposition was performed at direct current and
a 30 V voltage for 2 min. After that, the sample was
dried at room temperature for 24 h and calcined at
550oC for 2 h. Copper oxide was introduced by im-
pregnation of the support with a Cu(NO
followed by calcination in air flow at 550oC for 2 h.
The resulting sample contained 25 mg CuO and
100 mg Al
The copper3aluminum3calcium catalyst contain-
ing 20% CuO and 80% Talum, a mixture of calcium
mono- and dialuminates [3, 6], and platinum foil
were used for comparison.
Carbon monoxide was oxidized with atmospheric
oxygen in an automated catalytic installation with
forced circulation of the reaction mixture at various
CO : O
ratios and a total flow rate of 8 l h
reactor temperature was raised and lowered in small
steps, and time at which the system was kept at each
new temperature was sufficient to attain a constant
composition of the reaction mixture (commonly, up
to 10 min).
The CO content in the reaction mixture was de-
termined by gas chromatography (column 1.5 m long
and 2 mm in diameter, packed with a Porapak Q).