Catalysis Today 176 (2011) 314–317
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Catalysis Today
j ourna l ho me p ag e: www.elsevier.com/lo cate/cattod
Mechanochemical synthesis of double vanadate in Cu–Fe–V–O system and its
physicochemical and catalytic properties
Krystyna Wieczorek-Ciurowa
a,∗
, Jan Rakoczy
a
, Anna Bło ´ nska-Tabero
b
, El ˙ zbieta Filipek
b
,
Joanna Nizioł
a
, Piotr Dulian
a
a
Cracow University of Technology, Faculty of Chemical Engineering and Technology, Warszawska 24, 31-155 Cracow, Poland
b
West Pomeranian University of Technology, Department of Inorganic and Analytical Chemistry, Al. Piastów 42, 71-065 Szczecin, Poland
a r t i c l e i n f o
Article history:
Available online 12 January 2011
Keywords:
Mechanochemical synthesis
High-temperature synthesis
-,-Cu3Fe4(VO4)6
Steam reforming of methanol
a b s t r a c t
Mechanochemical synthesis has been successfully employed to prepare a Cu
3
Fe
4
(VO
4
)
6
powder. The
formation of designed compound (in -polymorphic form) is due to the reactions of copper, iron and
vanadium oxide precursors which were activated by high-energy ball milling (Activator 2S, Novosibirsk,
Russia) for 8 h instead of heat energy required in the conventional multi-stage high-temperature process
during 80 h forming -polymorphic form.
Catalytic properties of Cu
3
Fe
4
(VO
4
)
6
compound, which has been prepared by two different mentioned
above techniques, tested in the methanol steam reforming reaction are satisfactory and closely the same.
However, -, as well as, -polymorphic forms of Cu
3
Fe
4
(VO
4
)
6
are structural unstable during steam
reforming of methanol and form a metallic copper beside V
2
O
3
and iron oxides, which probably catalyze
simultaneously undesired methanation reaction. The real chemical mechanism is still not clear.
© 2010 Elsevier B.V. All rights reserved.
1. Introduction
The main task of our wide research is the creation of new
functional materials, which can be used for environmental pro-
tection, (e.g. processing of catalyst by mechanical treatment as
a method of green chemistry). Earlier investigations showed that
mechanochemical synthesis of solids by high-energy ball milling
can be used to preparing new compounds and this is an alterna-
tive method to the conventional high-temperature and ecological
hazardous syntheses [1–13].
Recently, special attention is focused on the catalysts’ finding for
low-temperature conversion of hydrocarbons to hydrogen [14–23].
Hydrogen can be produced from methanol by various processes.
The simplest one is its decomposition to CO and H
2
according to
reaction (1):
CH
3
OH
(g)
= CO
(g)
+ 2H
2
H
298
= +90.6 kJ mol
-1
(1)
The formed CO is converted to CO
2
in the water gas shift reaction
(reaction 2):
CO + H
2
O
(g)
= CO
2(g)
+ H
2(g)
H
298
= -41.1 kJ mol
-1
(2)
However, these two reactions can be performed in one step in
the process of catalytic steam reforming of methanol (SRM) (reac-
∗
Corresponding author. Tel.: +48 12 6282718; fax: +48 12 6282036.
E-mail address: kwc@pk.edu.pl (K. Wieczorek-Ciurowa).
tion 3):
CH
3
OH
(g)
+ H
2
O
(g)
catalyst
-→ CO
2(g)
+ 3H
2(g)
H
298
= +49.5 kJ mol
-1
(3)
The known catalysts for SRM are based mostly on copper dis-
persed in a carrier consisted of pure or mixed oxides e.g. ZnO, Al
2
O
3
and Zn–Al
2
O
3
, Cr
2
O
3
–Al
2
O
3
or ZrO
2
–Al
2
O
3
. They show high activ-
ity and high selectivity in low temperature range of 230–300
◦
C,
although they are not stable enough in the process [24–29].
The aim of presented study is the comparison the catalytic prop-
erties of Cu
3
Fe
4
(VO
4
)
6
, as a precursor of Cu-based catalyst in SRM
process synthesized by two different ways, i.e. mechanochemically
and in high-temperature processing.
2. Experimental
2.1. The synthesis of Cu
3
Fe
4
(VO
4
)
6
by mechanochemical
activation (MA)
Sample was synthesized by mechanochemical treatment of CuO
(p.a., Fluka), Fe
2
O
3
(pure, POCh) and V
2
O
5
(p.a., POCh) mixture
in molar ratio of 3:2:3, respectively. Milling was carried out in a
planetary ball mill (Activator 2S, Novosibirsk, Russia) using vial and
balls made of Cr–Ni steel. The milling conditions were as follows:
1200 rpm, BPR = 20:1, milling time up to 8 h, air atmosphere.
0920-5861/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.cattod.2010.12.007