298
V. A. Zazhigalov et al.
with high-temperature treatment [4]. The MoO 3 :CeO 2 nanofibers were obtained by
a combination of sol-gel method and electrospinning technique [2] in water-ethanol
solution with citric acid and polyvinyl alcohol addition. It is necessary to note that
all known traditional methods of preparation of CeO 2 -MoO 3 compositions used the
salts (NH 4 ) 6 Mo 7 O 24 × 4H 2 O and Ce(NO 3 ) 3 × 6H 2 O as raw materials.
In this study the ultrasonic treatment as alternative method for nanocomposites
preparation in Ce/Mo-O system was used. The commercial oxides of Ce and
Mo were utilized as raw materials which permit characterizing this method as
“environmentally clean” technology by the absence of harmful substances in
production and the possibility to simplify of synthesis realization. It is possible to
note that this technique was utilized for Ce(MoO 4 ) 2 nanoparticles preparation [3],
but the cerium and molybdenum salts and glucose as surfactant were used.
In this work the effect of sonochemical treatment on the properties of CeO 2 -
MoO 3 mixtures with different composition (CeO 2 /MoO 3 = 15:85, 25:75, 50:50,
75:25, molar ratio) was studied, and the structural, morphological, catalytic, and
sorption properties of the prepared samples were determined.
18.2 Experimental
18.2.1 Sample Preparation and Synthesis
The preparation of the initial cerium-molybdenum oxide compositions with a
molar ratio of CeO 2 /MoO 3 = 15:85, 25:75, 50:50, and 75:25 was realized by
mixing of CeO 2 and MoO 3 powders in agate mortar. All reagents employed were
commercially available and directly used without further purification. For the
sonochemical modification of composites, a dispersant UZDN-2 was used. The
powder mixture (10 g) was placed in glass reactor and irradiated in aqueous medium
during 1 h in effect of acoustic cavitation at a frequency of 22–40 kHz and a load
of 3 W/cm 2 . The temperature of the reaction medium was maintained at 80 ◦ C by
circulating cold water around the reactor. Obtained suspensions were filtrated and
dried in the air at 120 ◦ C.
18.2.2 Characterization Methods and Techniques
Powder X-ray diffraction measurements were carried out on a diffractometer PW
1830 (Philips) with monochromatic Cu Kα-radiation (λ ≈ 0.154 nm) in the range
from 10 ◦ to 90 ◦ (2). The average crystallite sizes (L) were estimated by using Eq.
(18.1), which is known as the Scherrer formula:
L =
Kλ
β cos
(18.1)
V. A. Zazhigalov et al.
with high-temperature treatment [4]. The MoO 3 :CeO 2 nanofibers were obtained by
a combination of sol-gel method and electrospinning technique [2] in water-ethanol
solution with citric acid and polyvinyl alcohol addition. It is necessary to note that
all known traditional methods of preparation of CeO 2 -MoO 3 compositions used the
salts (NH 4 ) 6 Mo 7 O 24 × 4H 2 O and Ce(NO 3 ) 3 × 6H 2 O as raw materials.
In this study the ultrasonic treatment as alternative method for nanocomposites
preparation in Ce/Mo-O system was used. The commercial oxides of Ce and
Mo were utilized as raw materials which permit characterizing this method as
“environmentally clean” technology by the absence of harmful substances in
production and the possibility to simplify of synthesis realization. It is possible to
note that this technique was utilized for Ce(MoO 4 ) 2 nanoparticles preparation [3],
but the cerium and molybdenum salts and glucose as surfactant were used.
In this work the effect of sonochemical treatment on the properties of CeO 2 -
MoO 3 mixtures with different composition (CeO 2 /MoO 3 = 15:85, 25:75, 50:50,
75:25, molar ratio) was studied, and the structural, morphological, catalytic, and
sorption properties of the prepared samples were determined.
18.2 Experimental
18.2.1 Sample Preparation and Synthesis
The preparation of the initial cerium-molybdenum oxide compositions with a
molar ratio of CeO 2 /MoO 3 = 15:85, 25:75, 50:50, and 75:25 was realized by
mixing of CeO 2 and MoO 3 powders in agate mortar. All reagents employed were
commercially available and directly used without further purification. For the
sonochemical modification of composites, a dispersant UZDN-2 was used. The
powder mixture (10 g) was placed in glass reactor and irradiated in aqueous medium
during 1 h in effect of acoustic cavitation at a frequency of 22–40 kHz and a load
of 3 W/cm 2 . The temperature of the reaction medium was maintained at 80 ◦ C by
circulating cold water around the reactor. Obtained suspensions were filtrated and
dried in the air at 120 ◦ C.
18.2.2 Characterization Methods and Techniques
Powder X-ray diffraction measurements were carried out on a diffractometer PW
1830 (Philips) with monochromatic Cu Kα-radiation (λ ≈ 0.154 nm) in the range
from 10 ◦ to 90 ◦ (2). The average crystallite sizes (L) were estimated by using Eq.
(18.1), which is known as the Scherrer formula:
L =
Kλ
β cos
(18.1)