The 3rd EMSES
International symposium Eco-Energy and Material Science and Engineering Symposium
6-9 April 2005, Chiangmai, Thailand
The Effect of Calcined Temperature on the Property of Nickel Oxide Catalyst
Synthesized by Sol-Gel Method
Chatchawan Sookmana, Paisan Kongkachuiychaya, and Waraporn Tanakulrungsankb
a
Department of Chemical Engineering, Kasetsart University, 50 paholyothin, Jatujak, Bangkok 10900,
Thailand.
b
Department of Industrial Chemistry, Rajamangala University of Technology Krungthep, Sathorn, Bangkok
10120, Thailand.
E-mail address: csookman@yahoo.com
Abstract
The objective of this work was to study the influence of calcined temperature on the property of received
nickel oxide catalyst, which was prepared via a sol-gel method. Nickel compounds; nickel nitrate, nickel
chloride and nickel sulfate, were used as precursor in solution form at concentration of 0.3, 0.5 and 0.7 M.
Sodium hydroxide aqueous solution of 2 M was added to each solution of nickel compounds to control the
pH of the solution at 9. The received green sol was washed with deionized water until the pH approached to
7. The solution was poured in the petri dish and, then dried at 80 C for 24 h. The obtained nickel hydroxide
gel was calcined at a temperature of 350, 550 and 750 C for 1 h. The products were characterized by using
SEM, XRD and BET. It was found that the degree of crystallinity of nickel oxide was increased with an
increase of the calcined temperature. All nickel oxide compounds showed the same result.
Keywords: Sol-gel method; nickel oxide; degree of crystallinity; calcined temperature.
Introduction
Metal oxides have been widely used for various
applications such as a semiconductor in dyesensitized solar cell, catalysts, fuel cells,
resistors, gas sensors, tranparent optical device,
optical coating and so on. The important one of
metal oxides is nickel oxide, which is used in
petrochemical industries. Reforming reaction of
methane and synthesis of olefin gas also used
nickel oxide in the process. Its many advantage
made our research group thought in synthesizing
nickel oxide catalyst. The nickel oxide catalyst
was prepared with sol-gel method because this
method provides high purity and uniformly
dispersed product. Moreover obtained particles
also were spherical shape. The study of effect of
calcined temperature on the properties of oxide
particles was investigated and major aim in this
work. Many literatures provided more
informations about characterizing obtained
particles when used different calcined
temprature. Sui-Wen Ho et al.[1] studied effect
of thermal treatment on the nickel state and CO
hydrogenation activity of titania supported nickel
catalysts. Catalyst samples were prepared by
impregnation method and then dried at 60,100
and 130C, at each temperature 2 h. After that
calcined at temperature of 400 and 600C for 4 h.
From the experiment showed the calcination
temperature plays a very important role in
catalytic activity of the studied catalyst. For this
catalyst the calcination at 600C gave higher
activity than the calcination at 400C. Miah
Muhammed et al.[2] prepared mesoporous TiO2
thin films by surfactant templating. TiO2
coatings were prepared by spin-coating at 2500
rpm for 30 s. After that TiO2 gel films were dried
at 90C for 24 h, and annealed at temperatures up
to 500C for 1 h in air. Films characterized by
X-ray diffraction showed when films were
annealed at 500C, TiO2 peaks were occurred
clearly. Shaobin Wang and G.Q.M. Lu [3]
studied CO2 reforming of methane on Ni
catalysts in part of effects of the support phase
and preparation technique. In this work the
catalysts were prepared by the co-precipitation
technique. A mixture of Ni(NO3)2 and Mg(NO3)2
solution was precipitated using NaOH solution
and then washed throughly to remove sodium.
After drying at 103-105C for overnight it was
calcined at 500C for 4 h. When received
catalysts were used in process at different
temperatures. At higher operated temperature,
the conversion was increased also. S.D. Jones
et al.[4] studied physical properties of sol-gel
aluminosilicates. Sol-gel-derived silicates were
prepared by hydrolysis of TEOS. For this, two
solutions were prepared. One contained TEOS
mixed with the appropriate solvent, and the other
a solution of aluminum nitrate nonahydrate in
deionised, distrilled water. When adjustment of
the hydrogen ion content of the reaction mixture
The 3rd EMSES
International symposium Eco-Energy and Material Science and Engineering Symposium
6-9 April 2005, Chiangmai, Thailand
was necessary, either nitric acid or ammonium
hydroxide were added to the aqueous solution.
Hydrolysis was performed by mixing the above
two solutions under continuous stirring at 298 K
in a water bath. For the systematic study of the
relationship between preparation conditions and
silicate pore structure, ratios of the reactants to
silicon were used. These were molar ratios in the
case of water, acid and aluminium and volume
ratios in the case of the solvents used. Before
calcination the sols were kept at ambient
conditions for two days. Conversion to their
oxides used a fixed thermal cycle where only the
limiting temperature was changed and heating
and cooling rates kept constant. This thermal
cycle used ramp rates of 10C/h and a 4 h dwell
period at the limiting temperature. When
calcination temperature
was varied
at
temperature of 473, 673 and 873 K, surface areas
from BET analysis decreased with an increase of
calcination temperature. Guo-Jun Li et al.[5]
done synthesis of nickel nanoparticles dispersed
in -alumina by heterogeneous precipitation.
-Al2O3-Ni composite powders were prepared
using NiO, Al(NO3)39H2O and NH3H2O as
starting materials. Mixed solution was stirred
until pH approach to 9,then obtained precipitates
were filtered and thoroughly washed three times
with distilled water. Finally, the precipitates were
calcined in air at 700 and 900C for 2 h at
a heating rate of 5C/min and the samples were
calcined at 900C and reduced at 700C for 4 h
in a hydrogen atmosphere at a heating rate of
5C/min. From the experiment, the crystal size
increased with an increase of calcination
temperature.
Experimental
The received nickel oxide catalysts prepared by
sol-gel method under base catalyzed systems.
The analytical grade reagents: Ni(NO3)26H2O,
NiSO46H2O, NiCl26H2O, NaOH and KOH were
used to prepared oxide particles. The nickel
compounds were varied concentration of 0.3, 0.5
and 0.7 M. After that 2 M of base, NaOH and
KOH, was added dropwise to each nickel
compounds solution and stirred continuously
until pH approach to 9. The green precipitate was
separated from the mother liquor. Then the slurry
was washed with deionized water until pH was
about 7 for dispose of impurity ions. After dried
at 80C for 24 h, the nickel hydroxide gel was
occurred following ionic equation (1).
Ni2+ + OH- = Ni(OH)2
(1)
When nickel hydroxide gel was calcined at
temperature of 350, 550 and 750 C for 1h, nickel
oxide particles were obtained follow equation
(2).
Ni(OH)2
NiO
(2)
Characterization
Powder X-ray diffraction (XRD) was measured
on a PHILIPS XRD PW 1830 using Cu K
radiation. Morphologies of the particles were
observed by JEOL Scanning Electron
Microscope. The BET surface areas were
calculated by the BET-multipoint method.
Results and discussion
The oxide particles obtained from calcining at
temperature of 350, 550 and 750C were grayblack powders. From X-ray diffraction analysis
(a)
(b)
Fig. 1. XRD patterns of NiO particles obtained
from 0.7 M of nickel nitrate and calcined at
temperature of 350, 550 and 750C for 1h. (a)
and (b) are XRD patterns of NiO particles
obtained by using NaOH and KOH respectively.
in Fig. 1(a) and (b) showed the crystal phase of
NiO, which was observed from three main peaks
at 2 theta about 38, 43 and 62.5. While NiO
The 3rd EMSES
International symposium Eco-Energy and Material Science and Engineering Symposium
6-9 April 2005, Chiangmai, Thailand
crystal received from using NaOH gave NiO
peaks
having
higher
intensity
than
another.Moreover degree of crystallinity was
increased with an increase of calcination
temperture, in Fig. 1. At 750C the NiO crystal
has the largest size when compared to other
temperatures. Because at higher temperature the
crystal has higher energy for growing. In Fig. 2.
Showed SEM microphotographs, the obtained
oxide particles synthesized at temperature of
750C gave spherical shape and good dispersion
in two cases.
Table 1 BET surface area of products calcined at
750C.
Type of Ni
compounds
0.7 M of Ni(NO3)2
0.7 M of NiCl2
0.7 M of NiSO4
base
NaOH
KOH
NaOH
KOH
NaOH
KOH
Calcined
temperature
, C
750
750
750
Surface
area, m2/g
5.5
5.4
5.4
5.2
3.1
2.9
Conclusion
The degree of crystallinity of nickel oxide was
increased with an increase of calcination
temperature, and NiO peaks obtained by using
NaOH gave higher intensity in all cases. To
compare the received oxide particles size showed
NiO synthesized by using NaOH provided a
good uniformly spherical shape. And the average
pore size of oxide particles was in range of
macropore in all cases.
Acknowledgements
This work was supported by Rajamangala
University of Technology Krungthep and
Centers of Excellence of Thailand Commission
of Higher Education, sponsored by ChE-ADB
Program, Department of Chemical Engineering,
Kasetsart University.
Fig. 2. SEM microphotographs of NiO catalysts
obtained from 0.7 M of nickel nitrate and
calcined at temperature of 350, 550 and 750C
for 1h. Left and right side are NiO particles
synthesized by using NaOH and KOH
respectively.
While NiO particles obtained by using NaOH
gave particle size having uniformly dispersed.
For the results of BET analysis showed in table
1, NiO particles prepared by using NaOH
provided a few higher surface area than another.
And the average pore size of oxide particles in
all cases was in range of macropore.
References
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Chen, “Effect of Thermal Treatment on the
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(1998) 178.
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