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Copyright American Scientific Publishers
RESEARCH ARTICLE
Copyright © 2013 American Scientific Publishers
All rights reserved
Printed in the United States of America
Journal of
Nanoscience and Nanotechnology
Vol. 13, 1639–1648, 2013
Fabrication and Photocatalytic
Properties of Self-Assembled In(OH)
3
and
In
2
O
3
Nano/Micro-Cubes
M. Muruganandham
1 2 ∗
, Mika E. T. Sillanpää
2
, Rominder P. S. Suri
1
,
Gang-Juan Lee
3
, J. J. Wu
3 ∗
, Bashir Ahmad
4
, and Yasushige Kuroda
4
1
Water and Environmental Technology (WET) Center, Department of Civil and Environmental Engineering,
Temple University, Philadelphia, Pennsylvania 19122, United States
2
Faculty of Technology, Laboratory of Green Chemistry, Lappeenranta University of Technology,
Patteristonkatu 1, FI-50100 Mikkeli, Finland
3
Department of Environmental Engineering and Science, Feng Chia University, Taichung 407, Taiwan, ROC
4
Department of Fundamental Material Science, Graduate School of Natural Science and Technology,
Okayama University, 3-1-1 Tsushima, Okayama 700-8530, Japan
This article reports a novel fabrication method for In(OH)
3
from indium oxalate by hydrothermal
process. Hydrothermal decomposition of indium oxalate at 180
C for 10 h results in In(OH)
3
. The
influence of hydrothermal experimental conditions such as temperature, time on the formation of
indium hydroxide was investigated. The self-assembly process was strongly influenced the exper-
imental conditions. The thermal decomposition of In(OH)
3
at 400
C results In
2
O
3
The synthe-
sized In(OH)
3
and In
2
O
3
were characterized using X-ray diffraction (XRD), field emission scanning
electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), ther-
mal analysis (TGA and DTA), diffuse reflectance spectra (DRS), and nitrogen adsorption analysis.
The XRD patterns indicated the formation of well crystallized cubic phase In(OH)
3
and In
2
O
3
. The
FE-SEM results indicated formation of In(OH)
3
and porous In
2
O
3
nano/micro-cubes. The photocat-
alytic activity of the synthesized In(OH)
3
was studied under UV light irradiation and results showed
that the In(OH)
3
photocatalyst was efficient for dye degradation. We proposed a plausible mecha-
nism for the formation of In(OH)
3
, and In
2
O
3
self-assembly.
Keywords: Indium Oxalate, In(OH)
3
, In
2
O
3
, Hydrothermal Decomposition, Self-Assembly.
1. INTRODUCTION
Recently, effort has been put to the synthesis controlled
semiconductor nanomaterials owing to their unique physi-
cal and chemical properties. Controlled fabrication of mate-
rials is important from both fundamental and application
point of view.
1–2
Self-assembled materials synthesis offers
unique advantages, such as mild experimental condition
and large scale fabrication, compared to template or struc-
ture directing reagents mediated synthesis.
3–5
Later pro-
cesses could often affect the structural integrality of the
materials, and moreover, templates removal needs addi-
tional energy and may inhibit the porous structures.
6
Therefore, the synthesis of well defined morphology with
∗
Authors to whom correspondence should be addressed.
controlled surface structure in a self-assembly process
is a challenging task for scientists. Indium hydroxide
(In(OH)
3
, and oxide (In
2
O
3
are important semiconduc-
tor materials possessing corresponding band gap energies
of 5.1 eV, and 3.6 eV, respectively. These semicon-
ductors have widely been used in various applications,
such as solar cell, field-emission display, lithium ion bat-
tery, nanoscale biosensor, gas sensor, optoelectronics and
photocatalysis.
7–11
Recently, various synthetic methodolo-
gies have successfully been used for In
2
O
3
fabrication.
7–11
Though various synthetic methods have been used, sim-
ple and cost effective routes to synthesize In
2
O
3
by uti-
lizing environmentally benign precursors are challenging
issues. Interestingly, microcubes, like In
2
O
3
morphology,
were fabricated using either InOOH or In(OH)
3
in a ther-
mal decomposition process at a suitable temperature.
12 13
J. Nanosci. Nanotechnol. 2013, Vol. 13, No. 3 1533-4880/2013/13/1639/010 doi:10.1166/jnn.2013.7143 1639