1070-4272/04/7702-0218 C 2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 2, 2004, pp. 218!221. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 2, 2004,
Original Russian Text Copyright + 2004 by Vasil’eva, Rudnev, Kondrikov, Tyrina, Reshetar’, Gordienko.
Catalytic Activity of Manganese-containing Layers
Formed by Anodic-Spark Deposition
M. S. Vasil’eva, V. S. Rudnev, N. B. Kondrikov,
L. M. Tyrina, A. A. Reshetar’, and P. S. Gordienko
Far-Eastern State University, Vladivostok, Russia
Institute of Chemistry, Far-Eastern Division, Russian Academy of Sciences, Vladivostok, Russia
Received April 10, 2003
Abstract-The catalytic activity of manganese oxide3containing anodic layers formed on titanium at room
temperature in CO oxidation to CO
Systems that contain MnO
, and Mn
catalyze numerous gas- and liquid-phase reactions
. In particular, they are used as catalysts for
CO oxidation to CO
[3, 5]. Manganese oxides are
commonly obtained by various chemical methods; for
are prepared by heating
salts, oxides, or hydroxides of manganese to 700 and
1000oC, respectively .
Previously, surface structures with thickness of
up to 60 mm, which contained, together with TiO
, have been obtained on
titanium by anodic-spark deposition at room temper-
ature from an electrolyte containing sodium tetrabo-
rate and salts of manganese . In the process, both
the phase composition and the content of manganese
in the coatings (0340 at. %) could be purposefully
altered by varying the concentration of manganese
salts and the forming modes.
This communication reports the results obtained in
evaluating the catalytic activity in CO oxidation of
manganese-containing structures formed on titanium.
Electrolytes were prepared using distilled water
and commercial reagents Na
O of chemically pure grade.
Anodic films were formed by means of electric break-
downs on VT1-0 titanium samples in the galvanostatic
mode (i = 0.2 A cm
) in the course of 4 or 10 min.
As current source served a thyristor converter with
unipolar current pulses. The process was performed
in the temperature range 13340oC. The specific fea-
tures of electrolyte preparation, the design of the elec-
trochemical cell and units for solution cooling and
agitation, and the method for electrode pretreatment
were described in .
The phase composition of the coatings was deter-
mined on a DRON-2.0 diffractometer (Cu
and the elemental composition, on a JXA-5A X-ray
fluorescence microanalyzer, with measurement error
of about 10%.
The molar ratio of the gaseous components changes
when the reaction 2CO + O
fore, a setup that comprised a 400-cm
and a pressure gage connected to it was used for eval-
uating the catalytic activity of the structures synthe-
sized, in the reaction of CO oxidation to CO
pressure gage provided measurements in the range
30.130 MPa with an accuracy of 5 0 10
ples with a total area of 40 cm
were placed in the re-
actor. Preliminarily, a 2 : 1 gas mixture of oxygen
and carbon(II) oxide with a total volume of 300 cm
was prepared volumetrically in a separate vessel.
A rarefaction was created in the reactor with a fore
pump. Then, the gas mixture prepared was admitted
into the reactor at room temperature and heated at
a rate of 20 deg min
. Simultaneously, the variation
of pressure within the reactor was recorded.
The composition of the gas mixture at the reactor
outlet was determined with an LKhM-8MD chro-
Figure 1a shows how the pressure in the reactor
varies with temperature in the presence (curves 1,
2) and in the absence (curve 3) of titanium with
manganese oxides in its surface layer. It can be seen
that, in the presence of manganese-containing layers,