Chemical Engineering Journal 170 (2011) 278–285
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Chemical Engineering Journal
journal homepage: www.elsevier.com/locate/cej
Modified single-phase hematite nanoparticles via a facile approach for
large-scale synthesis
Elahe Esmaeili
a
, Masoud Salavati-Niasari
a,b,∗
, Fatemeh Mohandes
b
, Fatemeh Davar
a
,
Hamideh Seyghalkar
b
a
Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, Iran
b
Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167, Iran
article info
Article history:
Received 6 June 2010
Received in revised form 19 February 2011
Accepted 5 March 2011
Keywords:
Iron oxide
Sugar
Nanoparticles
Chemical preparation
abstract
Shape- and size-controlled single-phase -Fe
2
O
3
(hematite) nanoparticles have been successfully syn-
thesized via a simple and facile thermal treatment route using modified precursors. At first, various
ferric-surfactant systems such as: ferric-sugars, ferric-hydrazine, ferric-oleic acid, and ferric-sugar-
hydrazine were prepared via a wet-chemical precipitation method and then, these intermediate adducts
as precursor were decomposed in at ordinary atmosphere to iron oxide. The morphology and particle
size of products were investigated by SEM and TEM images and XRD patterns. These results revealed that
the best quality -Fe
2
O
3
nanoparticles are synthesized through thermal decomposition of ferric-glucose
precursor with molar ratio of 1:8 heated at 500
◦
C in a step-wise manner.
© 2011 Elsevier B.V. All rights reserved.
1. Introduction
Considerable research has been focused on nanostructured
materials because of their wide range of important applications.
For example, nanostructures possess novel size-dependent proper-
ties, such as electrical, magnetic, mechanical, optical, and chemical
properties, which largely differ from those of their bulk materi-
als [1,2]. In recent years, the synthesis of magnetic nanostructures
has become a particularly important research field and is attracting
growing interest. Due to their advantages, such as chemical sta-
bility, biocompatibility, and low toxicity magnetic nanostructures
have been intensively studied not only for fundamental scien-
tific interest but also potential applications in biomedical fields,
especially in the field of targeted drug delivery [3–7]. The mag-
netic nanostructures used for drug delivery systems are usually
iron oxides. Fe
2
O
3
has four phases: -Fe
2
O
3
(hematite), -Fe
2
O
3
,
-Fe
2
O
3
(maghemite) and -Fe
2
O
3
[8]. Magnetic nanocrystals of
-Fe
2
O
3
have been applied in information storage, magnetic refrig-
eration, bioprocessing, controlled drug delivery and ferrofluids
[9,10] while -Fe
2
O
3
is environmental-friendly and of great inter-
est for potential applications as a gas sensor, lithiumion battery,
catalyst, and pigment [11–13]. So that, -Fe
2
O
3
, an n-type semi-
conductor (E
g
= 2.1 eV), is the most stable iron oxide under ambient
∗
Corresponding author at: University of Kashan, Institute of Nano Science and
Nano Technology, Kashan 87317-51167, Iran. Tel.: +98 361 591 2383;
fax: +98 361 555 2930.
E-mail address: salavati@kashanu.ac.ir (M. Salavati-Niasari).
conditions [14]. To date, the synthesis of hematite nanostruc-
tures have received wide attention. For example, uniform hollow
hematite spheres synthesized by direct hydrothermal treatment
of dilute FeCl
3
and H
3
PW
12
O
40
solution at 180
◦
C [15], -Fe
2
O
3
nanorings prepared by microwave-assisted process [16,17], -
Fe
2
O
3
nanoparticles with different morphologies of rhombohedra,
rods, and cubes obtained by the capping agent CTAB-mediated
hydrolysis of FeCl
3
[18], sol–gel synthesis of porous monolithic
Fe
2
O
3
solids from solutions of Fe (III) salts in various solvents
[19]. Camponeschi et al. applied a modified sol–gel processing
method to create iron (III) oxide nanoparticles in the presence
of propylene oxide as a gelation agent and an anionic surfactant,
sodium dodecylbenzene sulfonate (NaDDBS) [20]. In their applied
method, two metal salts were used as precursor, Fe(NO
3
)
3
·9H
2
O
and FeCl
3
·6H
2
O. They found that the addition of the NaDDBS
increases the gelation time for the FeCl
3
·6H
2
O and prevents
Fe(NO
3
)
3
·9H
2
O from forming a gel altogether. By using this sol–gel
method, hematite (-Fe
2
O
3
) nanoparticles were obtained from fer-
ric chlorate hexahydrate by adding NaDDBS before gel process and
after drying. Various iron oxyhydroxides such as -FeO(OH) and
-FeO(OH) were obtained from FeCl
3
·6H
2
O in the presence and
absence of NaDDBS, respectively. Hierarchically nanostructured
-Fe
2
O
3
hollow spheres were synthesized by thermal decom-
position of a precursor which was obtained using FeCl
3
·6H
2
O,
NaOH, and sodium dodecylbenzenesulfonate (SDBS) in the sol-
vent ethylene glycol via a facile microwave-assisted solvothermal
method [21]. It is reported that the formation of the precursor
may follow the reduction, dissolution, and recrystallization pro-
cess.
1385-8947/$ – see front matter © 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.cej.2011.03.010