J. Sci. Conf. Proceedings. 2008, Vol. 1, No. 1 1550-7033/2008/1/007/015 doi:10.1166/jbn.2008.002 7
1. INTRODUCTION
Metal oxides are an important class of chemicals having
wide-ranging applications in many areas of chemistry,
physics and material science.
1–5
In technological applications,
metal oxides are used in the fabrication of micro-electronic
circuits, sensors, fuel cells, and as catalysts.
6
In the emerging
field of nanotechnology, one goal is to make nanostructures
with special properties with respect to those of bulk
species.
7–11
Metal oxide nanocrystals can exhibit unique
physico-chemical properties due to their nano size and high
density of cover or edge surface sites.
Transition metal oxides (TMOs) have received considerable
attention in recent years for their catalytic, electronic and
magnetic properties.
12–14
Nano meter-sized metal oxides
are expected to possess better properties than those of
bulk metal oxides.
15–17
There are many routes for the
preparation of transition metal oxide nanocrystals
(TMONC). Generally, an appropriate salt of the transition
metal is oxidized by chemical or thermal treatments to
yield the corresponding metal oxide, and the size of the
resultant TMO can be controlled kinetically or thermody-
namically (by using templates). In recent years, methods
have been developed for the preparation of novel nano
structure of metal oxides. They can be generated by a
number of preparative methods that typically are described
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Vol. 1, 7–14, 2008
as physical and chemical methods.
18, 19
Conventional
methods for the preparation of metal oxide powder include
one-step solid state reaction at room temperature, thermal
decomposition of metal salts, mechanical milling of commercial
powders, and so on.
20–22
However, none of these methods seems
to be suitable for the preparation of highly dispersed oxide
nanocrystals, which has been found to be an obstacle to
many applications, especially in catalysts and electrode.
23, 24
Recently several new approaches have been developed
with the aim of obtaining well-dispersed oxide nanocrystals.
Nevertheless, few methods reported for preparation of
TMONC required large amounts of organic solvents and
expensive ultrasonic equipment.
25, 26
Now it becomes nec-
essary to adopt a very easy and low cast preparation
method of TMONC. Therefore, in the present communi-
cation, preparation of metal oxide nanocrystals (CuO,
NiO, Co
2
O
3
and MnO
2
) has been carried out via a novel
quick precipitation method.
27
The size of the nanocrystals
is controlled in this route by kinetic control, as the name
suggests. We have characterized the four TMO using pow-
der XRD, TEM and surface area measurements, and the
results suggest that TMOs produced are having sizes in the
nanometer range.
Ammonium perchlorate is the most common oxidizer in
composite solid propellants (CSPs). Thermal decomposition
characteristics of AP influence the combustion behavior
of the propellants.
28
AP based composite solid propellants
require combustion modifiers to achieve higher burning rates,
Preparation, Characterization and Catalytic Activity
of Transition Metal Oxide Nanocrystals
Gurdip Singh*
,1
, I. P. S. Kapoor
1
, Shalini Dubey
1
, and Prem Felix Siril
2
1
Chemistry Department, D. D. U. Gorakhpur University, Gorakhpur– 273009, India
2
University of Hudderfield, Hudderfield, HD1 3DH, UK
Nanocrystals of four transition metal oxides (TMOs) were prepared by a novel quick precipitation
method and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM).
From the XRD patterns, average particle sizes for CuO, NiO, Co
2
O
3
, MnO
2
are calculated to be 15
nm, 4 nm, 13 nm, 40 nm, respectively. The TEM study revealed that the majority of CuO particles are
of 6–8 nm in size. Catalytic activities of the TMO nanocrystals for thermal decomposition of ammo-
nium perchlorate (AP) were investigated using differential thermal analysis (DTA), thermogravimetric
analysis (TGA) and ignition delay measurements. The order of catalytic activity of these oxide
nanocrystals on thermal decomposition of AP was found to be: Co
2
O
3
> CuO > NiO > MnO
2
.
Keywords: Transition Metal Oxide Nano Crystal (TMONC), Ammonium Perchlorate, Catalytic
Activity, Thermal Decomposition.
RESEARCH ARTICLE
*
Author to whom correspondence should be addressed.