CJASR-12-13-133

Caspian Journal of Applied Sciences Research, 1(12), pp. 1-7, 2012

Available online at http://www.cjasr.com

ISSN: 2251-9114, ©2012 CJASR

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Full Length Research Paper

Synthesis and Characterization of Al2O3:Fe Nanoparticles Prepared via

Aqueous Combustion

Saeid Kakooei1*, Jalal Rouhi

2, Arash Dehzangi

3, Ehsan Mohammadpour

1, Mahmoud Alimanesh

2

1Department of Mechanic Engineering, UniversitiTeknologi PETRONAS, Tronoh 31750, Bandar Seri Iskandar,

Malaysia. 2Nano-Optoelectronic Research (NOR) Lab, School of Physics, Universiti Sains Malaysia, Malaysia.

3Institute of Microengineering and Nanoelectronics(IMEN) Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor,

Malaysia.

*Corresponding Author: [email protected]

Received 3 September 2012; Accepted 6 October 2012

Iron-doped Al2O3 nanoparticles were prepared via an aqueous combustion synthesis technique using

stoichiometric amounts of aluminum nitrate [(Al9NO3)3.9H2O], ferric nitrate [Fe(NO3)3.9H2O], and sucrose

(C12H22O11). The heat treatment of the nanoparticles at two temperatures (900 °C and 1100 °C) formed porous

agglomerated iron-doped alumina nanoparticles. The heat-treated powders were characterized by X-ray

diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Characterization results

showed existence of α-Al2O3 calcined at 1100 °C. In this study, iron-doped alumina particles with average

crystallite size (38.94 nm) were successfully synthesized by using sucrose as dispersion agent and carbon source.

Al2O3:Fe nanoparticles can be used in different fields as catalyst support and biocompatible material and for

electrical applications.

Key words: Nanomaterials; Iron Doped Alumina; Heat Treatment; Combustion Synthesis

1. INTRODUCTION

The combustion synthesis of Fe and Al2O3

composite method was reported by Holt and Kelly

for the first time in 1993 (Holt et al., 1993). This

method is a particularly safe, simple, and rapid

fabrication process, and its main advantages are its

time and energy efficiency (Mukasyan et al., 2007;

Deraz et al., 2009). The aqueous combustion

technique was recently used to synthesize alumina

nanopowders (Cordier et al., 2006; ZHAI et al.,

2006; Edrissi et al., 2007). However, the

combustion reaction mechanism is quite complex.

The main parameters influencing the reaction

include the main fuel type, ratio of fuels, fuel-to-

oxidizer ratio, pH level of the solution, amount of

excess oxidizer, and calcination rate. In general,

fuels should not react violently nor produce toxic

gases and must act as a complexing agent for metal

cations (Pathak et al., 2002; de Andrade et al.,

2006; Lima et al., 2006; Edrissi et al., 2008).

Alumina or α-Al2O3 (corundum) has been

widely investigated because of its important

applications in advanced engineering as, for

example, catalyst support (Breen et al., 2002),

biocompatible material, and nanocomposite for

structural and electrical applications (Pathak et al.,

2002; Toniolo et al., 2005; Meng et al., 2010). The

γ–α phase transition temperature can be decreased

by doping α-Fe2O3 (hematite) with alumina. In

addition, smaller α-Al2O3 particles can be

synthesized (Bye et al., 1974; Cordier et al., 2006).

Fe atoms in substitute solid solutions have been

known to change the diffusion properties of

alumina (Bataille et al., 2005). These effects are

related to the enhancement of the cation lattice

diffusion (via vacancies and interstitials) with rapid

oxygen diffusion in grain boundaries. The

diffusion changes are attributed to the presence of

Fe2+

cations which have relatively low solubility in

alumina. On the contrary, Fe3+

cations slightly

influence species diffusion properties and present

higher solubility in alumina (Bataille et al., 2005;

Cordier et al., 2006; Lucio-Ortiz et al., 2011).

Kobayashi et al. (2012) reported adding a small

quantity of Fe2O3 to the Al2O3 base catalyst

considerably enhanced catalyst stability and

catalytic activity (Kobayashi et al., 2012). The

doping agent modified catalytic behavior with an

influence on the morphology and textural porosity

in the alumina catalyst (Nomura et al., 2012).

mailto:[email protected]

Kakooei et al.

Synthesis and Characterization of Al2O3:Fe Nanoparticles Prepared via Aqueous Combustion

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The δ-Al2O3 is the primary intermediate phase

created from γ-Al2O3 containing Fe3+

in solid

solution, although crystallinity significantly

decreased with addition of Fe. The conversion rate

of intermediate phase to α-Al2O3 was increased by

the additions of Fe (Bye et al., 1974).

In this research, sucrose (C12H22O11) was used

as fuel and dispersion agent. Then, the effects of

different heat treatment temperatures on the

crystallite size of the combustion-synthesized α-

alumina powders were investigated. The powders

obtained via combustion synthesis were

characterized by X-ray diffraction (XRD),

scanning electron microscopy (SEM), differential

thermal analysis (DTA), and energy-dispersive X-

ray spectroscopy (EDX).

2. MATERIALS and METHODS

The iron-doped alumina nanoparticles were

prepared by using the solution combustion method.

Al(NO3)3.9H2O was used as an Al source, whereas

sucrose (C12H22O11) was used as a water-soluble

organic carbon source. As shown in Figure 1, 14.7

g aluminum nitrate and 12.86 g sugar were mixed

with deionized water respectively. Then, the

mixtures were combined to obtain a stable

suspension. Subsequently, 0.1 g of Fe(NO3)3·9H2O

was dissolved into the mixture.

Fig. 1: Schematic diagram of stages of Fe-doped Al2O3 nanoparticles synthesis by aqueous combustion method; (1)

Aqueous combustion reaction of mixtures leading to sponge-shape

The excess water from the mixtures was

evaporated on a hot plate until a gelatinous mixture

was formed. The chemical reaction of the

mentioned process is as follows:

2Al(NO3)3 + C12H22O11 + Fe(NO3)3 Al2O3 +

11H2O + 9NO2 + 6CO + 6C+Fe3+

+3e- (1)

The as-prepared powders were then submitted

to two thermal treatments in flowing air to obtain

the corundum (α) phase. The first heat treatment

was at 900 °C for 5 h, whereas the second heat

treatment was at 1100 °C for 5 h. Both heat

treatments utilized natural furnaces to cool the

heated powders to room temperature. The same

heating rate of 5 °C/min was applied to both

samples. The iron-doped alumina powders were

ground by using an agate pestle and mortar to

break the agglomerates. The schematic diagram of

these stages is shown in Figure 1.

All powders (as-prepared, calcined at 900 °C,

and calcined at 1100 °C) were examined via XRD

using Cu Kα radiation (Bruker D4 Endeavor). The

XRD data were analyzed to study the phase

formation and to identify unit cell parameters,

which were calculated using the “Eva” software. In

flowing air, differential thermal analyses (DTA,

Netzsch 404S) were performed on the powders

calcined at 900 °C and 1100 °C (from 25 °C to

1100 °C) at heating rates of 10 °C/min. Both

calcined powders were observed by using SEM.


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3. RESULTS and DISCUSION

The XRD patterns of the powders calcined at 900

°C and 1100 °C for 5 h are shown in Figure 2. The

α-Al2O3 and γ-Al2O3 phases are evident in the

sample calcined at 900 °C. Pure phase diffraction

peaks of α-Al2O3 were predominant in the XRD

patterns of the sample calcined at 1100 °C. This

finding is significantly consistent with earlier

results (Pathak et al., 2002; Peng et al., 2006; Jamil

et al., 2011). The peak broadening method was

used to calculate the average crystallite size.

The full width at half maximum (FWHM) of

the peak was measured and the average crystallite

sizes were estimated using the Scherrer equation:

(2)

Where D is the average crystallite size, λ the

wavelength of the radiation, θ Bragg’s angle and B

and b are the FWHMs observed for the sample and

standard, respectively. Terms B and 2θ were

obtained from XRD pattern. The average

crystallite size for each sample was calculated

using the above formula. The results demonstrated

that the average particle size of Al2O3:Fe

nanoparticles was about 38.94 nm.

The iron-doped alumina nanoparticles were also

subjected to DTA analyses to investigate the phase

transformations. Figure 3 shows that the DTA

curve has two significant steps. The curve for the

powder calcined at 900 °C first progressed upward

until 500 °C and then peaked at 1000 °C. However,

no peaks were observed at this temperature for the

powders calcined at 1100 °C because of the γ–α

phase transition during calcination. Edrissi et

al.(2007) have also observed this γ–α phase

transition at 1100 °C (Edrissi et al., 2007). The

DTA results confirmed the possibility of phase

transformation into a thermodynamically stable

crystallographic alpha alumina at about 1100 °C.

This finding is consistent with previous XRD data.

The SEM micrographs of the powders calcined

at 900 °C and 1100 °C for 5 h are shown in Figures

4 and 5. The synthesized powders are generally

foamy in nature and agglomerated. As shown in

Figure 5, the void formations on the powder

structures are created by the evolution of large

amounts of gases during combustion and heat

treatment. The sizes of the voids on the Al2O3:Fe

nanopowders significantly increased as the heat

treatment temperature increased. This development

can be a result of increasing gas moles, that is, the

agglomerates tend to break up and become more

porous. Toniolo et al. (Toniolo et al., 2005) and

Kishan et al. (Kishan et al., 2010) have also

observed the growth of void sizes due to increasing

gas moles.

The mixture compounds can be estimated via

EDX. Figure 6 shows the even distribution of Al,

O, and Fe elements. In addition, the figure clearly

shows that carbon already emerged. Table 1

summarizes the results of the energy-dispersive

analysis of the alumina samples sintered at 900 °C.

The values are given in weight and atomic percent.

4. CONCLUSION

Iron-doped alumina particles with average

crystallite sizes (38.94 nm) were successfully

synthesized by using sucrose (C12H22O11) as fuel

and dispersion agent. The results show that

combustion synthesis has more outstanding

potential in producing nanocrystalline iron-doped

alumina powders compared with other

conventional methods. As a water-soluble organic

carbon source, sucrose had a significant influence

on the synthesis of Al2O3:Fe nanopowders via the

carbothermal reduction during the combustion

synthesis. The characteristics of the produced

nanopowders significantly depend on the total

effects of releasing gas and heat. More specifically,

higher calcination temperatures resulted in

crystallite growth and agglomeration. Fe doped

alumina nanoparticles are widly used in different

fields such as catalyst support, biocompatible

material, and electrical applications.

2 2

0.9

cosD

B b

Kakooei et al.


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Fig. 2: The XRD patterns of Al2O3:Fe powders calcined at a) 900 °C and b) 1100 °C for 5h


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Fig. 3: The DTA curve of Al2O3:Fe powders calcined at 900 °C and 1100 °C

Fig. 4: SEM images of the Al2O3:Fe powders heated at 900 °C

Kakooei et al.


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a

Fig. 5: SEM images of the Al2O3:Fe powders heated at 1100 °C

Fig. 6: EDX spectra of iron doped alumina nanoparticles calcined at 900 °C

REFERENCES

Bataille A, Addad A, Crampon J, Duclos R (2005).

Deformation behaviour of iron-doped

alumina. Journal of the European Ceramic

Society, 25(6): 857-862.

Breen J, Burch R, Coleman H(2002). Metal-

catalysed steam reforming of ethanol in the

production of hydrogen for fuel cell

applications. Applied Catalysis B:

Environmental, 39(1): 65-74.

Bye G, Simpkin G (1974). Influence of Cr and Fe

on Formation of α‐Al2O3 from γ‐Al2O3.

Journal of the American Ceramic Society,

57(8): 367-371.

Cordier A, Peigney A, De Grave E, Flahaut E,

Laurent C (2006). Synthesis of the

metastable α-Al1.8/ Fe 0.2/O 3 solid solution

from precursors prepared by combustion.

Journal of the European Ceramic Society,

26(15): 3099-3111.

De Andrade M, Lima M, Bonadiman R, Bergmann

C (2006). Nanocrystalline pirochromite

spinel through solution combustion

synthesis. Materials research bulletin,

41(11): 2070-2079.


7

Deraz N, Shaban S (2009). Optimization of

catalytic, surface and magnetic properties of

nanocrystalline manganese ferrite. Journal of

Analytical and Applied Pyrolysis, 86(1):

173-179.

Edrissi M, Norouzbeigi R (2007). Synthesis and

characterization of alumina nanopowders by

combustion of nitrate-amino acid gels.

Materials Science-Poland, 25(4): 1029-1040.

Edrissi M, Norouzbeigi R (2008). Taguchi

Optimization for Combustion Synthesis of

Aluminum Oxide Nano‐particles. Chinese

Journal of Chemistry, 26(8): 1401-1406.

Holt JB, Kelly M (1993). Combustion synthesis

method and products, Google Patents.

Jamil RS, Abdul Razak K, Ahmad NF, Mohamad

H (2011). The Effect of Fuel Types on

Porous Alumina Produced via Soft

Combustion Reaction for Implant

Applications. Journal of Materials

Engineering and Performance: 1-6.

Kishan J, Mangam V, Reddy B, Das S, Das K

(2010). Aqueous combustion synthesis and

characterization of zirconia-alumina

nanocomposites. Journal of Alloys and

Compounds, 490(1-2): 631-636.

Kobayashi S, Kaneko S, Ohshima M, Kurokawa

H, Miura H (2012). Effect of iron oxide on

isobutane dehydrogenation over Pt/Fe 2 O3 -

Al2O3 catalyst. Applied Catalysis A:

General, Volumes 417–418: 306–312.

Lima M, Bonadimann R, de Andrade M, Toniolo J,

Bergmann C (2006). Nanocrystalline Cr 2 O

3 and amorphous CrO3 produced by solution

combustion synthesis. Journal of the

European Ceramic Society, 26(7): 1213-

1220.

Lucio-Ortiz CJ, De la Rosa JR, Ramirez AH, De

los Reyes Heredia JA, del Angel P, Munoz-

Aguirre S, De León-Covián LM (2011).

Synthesis and characterization of Fe doped

mesoporous Al2O3 by sol–gel method and its

use in trichloroethylene combustion. Journal

of sol-gel science and technology, 58(2):

374-384.

Meng FC, Tian ZQ, Zhang F, Tian CC, Huang WJ

(2010). Combustion Synthesis of

Nanocrystalline Al2O3 Powders Using Urea

as Fuel: Influence of Different Combustion

Aids. Key Engineering Materials, 434: 868-

871.

Mukasyan A, Dinka P (2007). Novel approaches to

solution-combustion synthesis of

nanomaterials. International Journal of Self-

Propagating High-Temperature Synthesis,

16(1): 23-35.

Nomura K, Kinoshita R, Sakamoto I, Okabayashi

J, Yamada Y (2012). Dilute magnetic

properties of Fe doped Al2O3 powders

prepared by sol-gel method. Hyperfine

Interactions: 1-5.

Pathak L, Singh T, Das S, Verma A,

Ramachandrarao P (2002). Effect of pH on

the combustion synthesis of nano-crystalline

alumina powder. Materials Letters, 57(2):

380-385.

Peng T, Liu X, Dai K, Xiao J, Song H (2006).

Effect of acidity on the glycine-nitrate

combustion synthesis of nanocrystalline

alumina powder. Materials research bulletin,

41(9): 1638-1645.

Toniolo J, Lima M, Takimi A, Bergmann C

(2005). Synthesis of alumina powders by the

glycine-nitrate combustion process.

Materials research bulletin, 40(3): 561-571.

Zhai X, Fu Y, Chu G (2006). New Technology

Reports Combustion synthesis of the

nano/structured alumina powder.

Nanoscience, 11(4): 286-292.

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CJASR-12-13-133