Synthesis, characterization, and catalytic performance of La1-xCexNi1-yZryO3 perovskite nanocatalysts in dry reforming of methane

Article abstract of DOI:10.13005/ojc/340337

La_1-xCe_xNi_1-yZr_yO₃ perovskite nanocatalysts were prepared by a method called citrate sol-gel. The samples were studied by the methods as X-ray diffraction (XRD), temperature programmed reduction (TPR), and inductively coupled plasma (ICP) technique.The BET method was used to determine the specific surface area. In addition, scanning and transmission electron microscopy techniques were employed to study the morphology of the prepared samples³¹. The XRD patterns confirmed the formation of perovskite with well-crystallized structure in doping level up to x= 0.1 and y= 0.2. The results of morphology studies revealed that homogenous particles in nanometer range were achieved. Based on the TPR analysis, reduction process occurred at higher temperatures and became difficult as the doping level of Zr increases. The catalytic performance was studied in dry reforming of methane (DRM) with CO₂. The catalyst La_0.9Ce_0.1Ni_0.8Zr_0.2O₃ perovskite provides the highest catalytic performance. CH4 conversion was more than 60%, CO₂ conversion was more than70% and the H2/CO molar ratio was ~1, respectively. Catalytic activity of La_1-xCe_xNi_1-yZr_yO₃ nanocatalysts was enhanced when the doping level of Zr (y) increased up to 0.2, and the following result was obtained for H2/CO ratio: LaNiO₃ > La_0.9Ce_0.1Ni_0.8Zr_0.2O3 > La_0.9Ce_0.1Ni_0.9Zr_0.1O₃ > La0.9Ce0.1Ni O₃

Full text of DOI:10.13005/ojc/340337

ISSN: 0970-020 X
CODEN: OJCHEG
2018, Vol. 34, No.(3):
Pg. 1469-1477
ORIENTAL JOURNAL OF CHEMISTRY
An International Open Free Access, Peer Reviewed Research Journal
www.orientjchem.org
Synthesis, Characterization, and Catalytic Performance of
La1-xCexNi1-yZryO3 Perovskite Nanocatalysts in Dry
Reforming of Methane
PARASTOO DEZvAREHA2, HAMIDREZA AgHAbOZORgb*1,2,
MOAYAD HOSSAINI SADRC2 and KARIM ZARED2
1,2Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran.
2Research Institute of Petroleum Industry, Tehran, Iran.
*Corresponding author E-mail: dezvarehparastoo38@gmail.com
http://dx.doi.org/10.13005/ojc/340337
(Received: August 03, 2017; Accepted: January 17, 2018)
AbSTRACT
La1-xCexNi1-yZryO3 perovskite nanocatalysts were prepared by a method called citrate sol-gel.
The samples were studied by the methods as X-ray diffraction (XRD), temperature programmed
reduction (TPR), and inductively coupled plasma (ICP) technique.The BET method was used to
determine the specific surface area. In addition, scanning and transmission electron microscopy
techniques were employed to study the morphology of the prepared samples31. The XRD patterns
confirmed the formation of perovskite with well-crystallized structure in doping level up to x= 0.1
and y= 0.2. The results of morphology studies revealed that homogenous particles in nanometer
range were achieved.Based on theTPR analysis, reduction process occurred at higher temperatures
and became difficult as the doping level of Zr increases. The catalytic performance was studied in
dry reforming of methane (DRM) with CO2. The catalyst La0.9Ce0.1Ni0.8Zr0.2O3 perovskite provides
the highest catalytic performance. CH4 conversion was more than 60%, CO2 conversion was more
than70% and the H2/CO molar ratio was ~1, respectively. Catalytic activity of La1-xCexNi1-yZryO3
nanocatalysts was enhanced when the doping level of Zr (y) increased up to 0.2, and the following
result was obtained for H2/CO ratio:
LaNiO3 > La0.9Ce0.1Ni0.8Zr0.2O3 > La0.9Ce0.1Ni0.9Zr0.1O3 > La0.9Ce0.1Ni O3
Keywords: Nanocatalyst, Catalytic performance, Perovskite, Dry reforming of methane (DRM).
INTRODUCTION
based on CO2 consuming and H2 production in
order to solve the global warming such as dry
reforming of methane (DRM)1-3. Methane dry
reforming applies greenhouse gases including CH4
and CO2 to produce syn-gas (H2+CO)30.Syn-gas
Greenhouse gases such as CO2 and CH4
cause global warming that is one of the greatest
problem worldwide. There are many researches
This is an
Open Access article licensed under a Creative Commons Attribution-Non Commercial-Share Alike
4.0 International License (https://creativecommons.org/licenses/by-nc-sa/4.0/), which permits unrestricted
Non Commercial use, distribution and reproduction in any medium, provided the original work is properly cited.

1470
AGHABOZORGB et al., Orient. J. Chem., Vol. 34(3), 1469-1477 (2018)
is used in Fischer–Tropsch synthesis method to
generate different chemicals4-8. Many of perovskite
oxides behave as catalysts in the production of
syn-gas regarding their stability9-12. ABO3 formula of
perovskites contains lanthanides, alkali metals, and
alkali earth metals as A-site and transition metals
are inserted in the B-site15. The active site in the
perovskite oxide is the B-site, while the stability of
the perovskite is affected by the A-site metal. The
proper interaction of A and B-site metals increases
the catalytic performance13,14,16. The dry reforming
of methane employs carbon dioxide (as an oxidant)
and methane on the surface of Ni-based perovskites
which are resistant to coking15. The reactions that
can occur in the dry reforming of methane are
endothermic as below33:
to the activation of these oxide systems. The
reducing process should take place on the catalyst
bed15. Variable chemical methods such as sol-gel,
co-precipitation, hydrothermal, and aerosol are
applied to produce nano-sized perovskites. In the
present research, La1-xCexNi1-yZryO3 perovskites with
various doping level up to x= 0.1 and y= 0.3 were
obtained. The catalytic behavior was evaluated in
DRM30.
ExPERIMENTAL
Preparation of catalysts
La1-xCexNi1-yZryO3 samples have been
synthesized by a method called citrate sol-gel.
Stoichiometric amounts of the cations at A and
B sites were applied. La(NO3)3.6H2O (Merck &
Co., >99/9%), Ce(NO3)3.6H2O (Merck & Co.,
>99%), Ni(NO3)2.6H2O (Merck & CO., >99%),32
ZrO(NO3)2.6H2O, (Aldrich, 99/99%)43, ethylene
glycol (99%), and citric acid (Merck & Co., 99/5%)
were used30,41. A solution (1M) consisting of proper
stoichiometric amounts of lanthanum, cerium, nickel
nitrates, and zirconium oxynitrate were prepared and
CH4+ CO2 ↔ 2CO + 2H2
CO2 + H2 ↔ H2O + CO
DH298k=247kJ/mol (1)
DH298k = 41 kJ/mol (2)
Partially substituting at A and B sites,
affects the stability, structural defect formation,
oxygen mobility in crystal lattice34, oxygen storage,
coke resistance, and catalytic activity35,38,42
.
stirred for 40 min. at 60 C30. The ethylene glycol
o
Some examples of La substitution in La1-xMxNiO3
that promotes catalytic performance are
M=Ce15-17and Sr18.Resultingcompoundsareresistant
to deposition of carbon because of numerous oxygen
vacancies and presence of Ni crystallite size.
Catalysts that are Ce- substituted improve catalytic
behavior because they have sufficient capacity of
oxygen storage and high mobility of lattice oxygen16.
Based on Sutthiumporn et al.,18 researches, B-site
substitution leads to better catalytic performance and
structural stability.Gallego et al., studied La1-xAxNiO3-d
perovskite, in which lanthanum was substituted by
cerium and praseodymium, and investigated its
catalytic performance and coke resistance in DRM2.
Jahangiri et al.,19-20 investigated the performance
of perovskite-type oxides La1–xSmxNiO3 and
LaNi1–xFexO3 in combined reforming of methane
(CRM) by changing the substitution degrees (x).
Goldwasser et al.,21 studied the partial substitution
influence of Ru by Ni and La by Ca in LaRuO3
and LaRu0.8Ni0.2O3, respectively in CRM and DRM
processes. Structural defects of the perovskite
oxides can be formed by doping different metallic
elements at A or B sites to increase its catalytic
activity. The reduction of the metal on B site leads
and citric acid (1M) were added. The sol forming
started and the extra water evaporated during 8 h
o
at 80 C30. The sol transformed to an amorphous
spongy gel.The gel was dried for 24 h at 110 oC and
calcined within 2 h at 800 oC.The rate of heating was
1oC/min. as it reached 350 oC and 3 oC/min. until it
reached 800 oC.
Characterization techniques
In order to determine the crystallite
structure, purity of phase and the size of the
particle, X-ray patterns were studied. A 3003 PTS
diffractometer, prepared the X-ray diffraction patterns
of the synthesized samples37. The copper anode
was applied in this equipment20. The observed
X-ray patterns of the catalyst were compared with
the JCPDS database that leads to identification of
the phases40. Scanning electron microscopy (SEM)
was used to study the morphology of the catalysts
by employing a Philips XL30 microscope and
transmission electron microscopy (TEM) applying
Philips CM200 FEG microscope30. Temperature-
programmed reduction (TPR) is a technique for
determination of reduction properties of the samples.
In this technique semi-automatic micrometricsTPD/

1471
AGHABOZORGB et al., Orient. J. Chem., Vol. 34(3), 1469-1477 (2018)
TPR 29000 apparatus was applied30. Based on
the BET method, a Tristar 3000 Micrometrics was
employed to measure the specific surface areas
of the samples. In this method, N2 at 200°C was
used. Inductively coupled plasma (ICP) emission
spectroscopy, measured the quantitative analysis
of metals30.
LaNiO3 perovskite phase based on (JCPDS No.:
88-633)15,30. For doping level of x= 0.1 and y= 0.0,
detailed examination of this pattern also revealed the
perovskite phase of La0.9Ce0.1NiO3. For substitution
degree of x= 0.2, the diffraction lines of XRD pattern
are characteristic of the perovskite, and also NiO and
CeO2 oxides15.The XRD patterns of the synthesized
La0.9Ce0.1Ni1-yZryO3 are seen in Fig. 2. The XRD
patterns of these samples confirm that Zr doping
level (y) up to 0.2 have led to the formation of mono
phase and well-crystallized perovskite structure.
Beyond y= 0.2, additional peaks are appeared which
belong to CeO2, NiO, and La2Zr2O7 oxides.
Measuring catalytic activity
The experimental studies and evaluation
tests of the catalytic activity were carried out in a
micro-reactor applying highly pured feed gases (CH4,
CO2, N2 and H2)20. Controllers of the mass flow were
Brooks Instrument, Model 5850.Two thermocouples
and PID thermo-controllers measured and controlled
the temperature of micro-reactor.0.4 g of the catalyst
was loaded in the reactor for all case studies.
The flow rate of feed gases was 100 mL/min.
(WHSV=15L/(h.g),CH4/CO2=1/1)underatmospheric
pressure30. The temperature was between 600°C
and 800 °C36. A gas chromatograph analyzed the
products and reactants with FID andTCD detectors.
Before measuring the activity of catalysts, the
precursors should be reduced to produce the metal
phase in a mixture of 20% H2/N2 for 2 h at 700°C.
The rate of flow should be 50 mL/min.30. In all tests,
the performance of the catalysts were evaluated by
conversions. Conversions of CH4 and CO2, yields
of H2 and CO, and H2/CO ratios based on the
endothermic reactions attributed to this process were
defined as follow10,39
p Perovskite (JCPDS No.: 88-833)
+ NiO (JCPDS No.: 22-1189)
# La2NiO4 (JCPDS No.: 83-1164) * CeO2
(JCPDS No.: 44-1001)
Fig. 1. xRD patterns of La1-xCexNiO3 nanocatalysts
RESULTS AND DISCUSSIONS
Characterization of the La1-xCexNi1-yZryO3 samples
Crystalline structure
The XRD patterns of the La1-xCexNiO3
samples for x up to 0.2 and y= 0.0 are shown in
Fig. 1. In the case of the Ce & Zr-free sample
(x= 0.0 and y= 0.0), diffraction lines belong to the
* CeO2 (JCPDS No.: 2-1306)
#La2Zr2O7 (JCPDS No.: 50-837)
+ NiO (JCPDS No.: 4-835)
pPerovskite (JCPDS No.: 88-633)
Fig. 2. XRD patterns of La0.9Ce0.1Ni1-yZryO3 nanocatalysts

1472
AGHABOZORGB et al., Orient. J. Chem., Vol. 34(3), 1469-1477 (2018)
Chemical analysis and surface area measurement
Table1showsthesurfaceareaandchemical
of the catalysts based on BET method are in the
range of 3-6 m2g-1. Low surface area solids are the
result of high temperatures exposure for long time.
Scherrer equation was applied by employing the
intense peak to determine the crystallite size of the
obtained samples.The samples contain particles of
the size in nanometers as the results confirmed.
composition (wt.%) for synthesized samples. The
experimental data and the nominal value are close
to each other for La, Ce, Ni, Zr (wt.%) based on ICP
technique30.The reported values in parenthesis are
nominal values. The results determine that a proper
method was applied in this research. Surface areas
Table 1: Crystallite size, surface areas, and elemental analysis of some La1-xCexNi1-yZryO3
perovskites (calculated by Scherrer equation)
La1-xCexNi1-yZryO3
X
y
La (wt.%)* Ce (wt.%)
Ni (wt.%)
Zr (wt.%)
SA (m2/g)
D (nm)
0
0.1
0.1
0
0.1
0.2
69.8 (70.2)
62.2 (62.5)
61.2 (61.4)
0.0 (0.0)
7.0 (6.8)
6.9 (6.8)
30.2 (29.8)
26.3 (26.5)
23.0 (23.1)
0.0 (0.0)
4.5 (4.2)
8.9 (8.7)
6
3
5
51
45
43
* Nominal values in parenthesis
Morphology
Morphology studies of the perovskites
were accomplished by SEM and TEM techniques.
Figs. 3 and 4 (SEM and TEM images), reveal a
uniform texture of spherical particles. The particle
sizes are in nanoscale which is in consistent with
crystallite sizes that calculated by Scherrer equation
(see Table 2).
(C)
Fig. 3. SEM images of La0.9Ce0.1Ni1-yZryO3 ((y = 0.1) (A),
(y = 0.2) (b), (y = 0.3) (C)).
(A)
Fig. 4.TEM image of La0.9Ce0.1Ni0.8Zr0.2O3 perovskite
Reducibility study of La1-xCexNi1-yZryO3
Since active sites for the reforming
reaction in La1-xCexNi1-yZryO3 samples are nickel
and zirconium, the samples have to be reduced in
(B)

1473
AGHABOZORGB et al., Orient. J. Chem., Vol. 34(3), 1469-1477 (2018)
order to be activated prior to the reaction. After the
reduction process, Ni and Zr highly scattered on
a matrix of La–Ce–O and the metal catalyst was
produced. Therefore, temperature-programmed
reduction is applied to study the reducibility of
La1-xCexNi1-yZryO3, (Fig. 5). The reduction of LaNiO3
perovskite occurs in two steps. The maximum
points of the peaks were apparent at 408 and
505 oC22-23. The first peak can be assigned to
reducing of Ni3+ to Ni2+ that corresponds to La2Ni2O5
forming15. The second peak can be attributed to
reduction of Ni2+ to NiO. Cerium doped perovskites
(La1-xCexNiO3), show slight shift to lower temperatures
in TPR profile2. It has been reported24 that, the
reduction becomes easier while the energy of metal-
oxygen bond2,15,24 decreases. In this case study, for
La0.9Ce0.1NiO3 sample, by decreasing the ionic radius
in A-site from 103.2 pm (La3+) to 101 pm (Ce3+),
metal–oxygen bond energy has been decreased2.
Thus, the ease of reduction is achieved. With
doping Zr into the perovskite samples (La0.9Ce0.1Ni1-
yZryO3), the reduction is occurred in four steps. The
peaks at lower and higher temperatures can be
attributed to reducing of Ni3+ to Ni2+ and Zr2+ to ZrO,
respectively20. The broad peak at intermediate can
be allocated to reducing of Ni2+ to NiO and Zr4+ to
Zr2+ in the perovskite structure25-26. In other words,
the partial replacement of nickel by zirconium in the
perovskite structure made the metal reduction more
difficult and the maximum of the peaks shifted to
higher temperatures. Since Zr ion is more resistant
to reduction than Ni ion in the ABO3 perovskite, the
Zr ions would be reduced at higher temperatures18.
Fig. 5.TPR profiles of prepared La0.9Ce0.1Ni1-yZryO3 calcined in air at 800 oC
Catalytic activity
Catalytic behavior of the obtained
containing La0.9Ce0.1Ni1-yZryO3 with doping level of
y=0.1 and y=0.2. It can be concluded that the
reaction equation 1 may be the main reaction30.
Based on these results, mono phase perovskites
are proper to produce more H2. H2/CO ratio is less
than 1 where Zr doping level of the applied catalyst
is y>0.2 and has more than one phase. In samples
without Zr (La0.9Ce0.1NiO3) this ratio is also less
than 1. In Fig. 7 the CH4 & CO2 conversions, and
H2 & CO yields versus time for La0.9Ce0.1Ni1-yZryO3
samples are presented.These diagrams reveal that
in reactions containing the pure perovskite, CH4 &
CO2 conversions and H2 & CO yields are higher in
comparison with reactions containing more than one
phase. In reactions containing La0.9Ce0.1Ni0.8Zr0.2O3
catalyst the H2/CO ratio is ~1 with the best catalytic
performance (Fig. 8). In reactions containing
compounds has been considered for DRM process.
The temperature was between 600 to 800 oC38.The
CH4 & CO2 conversions and H2 & CO yields in various
temperatures, in the presence of La0.9Ce0.1Ni1-yZryO3
are prepared in Fig. 6. CH4 and CO2 conversions
grow by rising the temperature. The conversions
of CO2 are higher than that of CH4. It can be the
result of CO2 consuming in reaction equations 1
and 2.Consequently, by rising reaction temperature,
both H2 and CO yields increase and the CO yields
are higher than that of H2. This feature is more
notable at higher temperatures. In reactions with
La0.9Ce0.1Ni1-yZryO3 catalyst that the partial doping
level is y= 0.3, there is not notable product yields at
any temperature. H2/CO ratio is ~1, in the reactions

1474
AGHABOZORGB et al., Orient. J. Chem., Vol. 34(3), 1469-1477 (2018)
La1-xCexNi1-yZryO3 samples, the content of Ce and
Zr control the CH4 and CO2 conversions in DRM
process. Redox chemistry, heat stability, ionic
conductivity and the oxygen transporting capability
of Zr is notable in proper catalytic behavior of
these nanocatalysts27-29. High redoxability of cerium
upgrades the catalytic characteristic of Ni-based
catalysts2 in DRM30.
Fig. 6 Conversions of CH4 and CO2, and H2 and CO yields versus temperature for
La0.9Ce0.1Ni1-yZryO3 samples in DRM process (CH4/CO2= 1/1 and WHSv=15L/(h.g)).

1475
AGHABOZORGB et al., Orient. J. Chem., Vol. 34(3), 1469-1477 (2018)
Fig. 7. Conversions of CH4 and CO2, H2 and CO yields versus time for La0.9Ce0.1Ni1-yZryO3
samples at 750 oC in DRM process (CH4/CO2= 1/1 WHSv=15L/(h.g)).

1476
AGHABOZORGB et al., Orient. J. Chem., Vol. 34(3), 1469-1477 (2018)
Fig. 8. H2/CO ratios for La1-xCexNi1-yZryO3 versus time in DRM
process (CH4/CO2= 1/1 WHSv=15L/(h.g))
CONCLUSION
consequently, the metal reduction shift to
higher temperatures.
1.
2.
The perovskite La1-xCexNi1-yZryO3 (x=0.1,
y=0.1, 0.2) nanocatalysts were prepared by a
methodcalledcitratesol-gel.Sphericalparticles
on a nanometer scale were produced.
Based on TPR analysis, partial substitution
of Ni by Zr in La0.9Ce0.1Ni1-yZryO3 perovskite
led to a difficult reducibility of nickel, and
3.
4.
By rising the temperature, CH4 & CO2
conversions and the yields of H2 & CO
increased, while the pure perovskite was
present in the reaction.
Par tially substituted perovskite
La0.9Ce0.1Ni0.8Zr0.2O3 performed the best
catalytic activity.
REFERENCES
A.; Catal. Today., 2006, 113, 194-200.
Gallego, G. S.; Mondragon, F.; Barrault, J.;
Tatibouet, J. M.; Dupeyrat, C. B. Appl. Catal
A: Gen., 2006, 311, 164-71.
Mawdsley, J. R.; Krause, T. R. Appl. Catal.,
2008, 334, 311-312.
Chendong, Z.; Doris, S.; Balachandran, U.;
Meilin, L. Chem. Mater., 2006, 18, 4647-
4650.
Pereniguez, R.; Gonzalez-Dela Cruz, V. M.;
Holgado, J. P.; A. Caballero, Appl. Catal.,
2010, 93, 346-353.
1.
2.
3.
4.
Valderramaa, G.; Kiennemannb, A.;
Goldwasser, M. R. Power Sources., 2010,
195, 1765-1771.
11.
Gallego German, S.;Marin Jaime, G.;Batiot-
Dupeyrat, C.; Barrault, J.; Mondragon, F.;
Appl. Catal. A: Gen., 2009, 369, 97-103.
Steinhauer, B.; Kasireddy, M.R.; Radnik, J.;
Martin, A. Appl. Catal. A: Gen., 2009, 366,
333-341.
Bedel, L.; Roger, A. C.; Estournes, C.;
Kiennemann, A.; Catal. Today., 2003, 85,
207-218.
12.
13.
14.
15.
16.
17.
Lima, S. M.; Assaf, J. M.; Pena, M. A.; Fierro,
J. L. G. Appl. Catal., 2006, 311, 94-104.
Choi, S.;Moon, S.H.Catal.Today., 2009, 146,
148-153.
Lima, S.M.;Silva, A.M.;Costa, L.O.O.;Assaf,
J. M.;Mattos, L.V.;Sarkari, R. Appl. Catal. B.,
2012, 121, 1-9.
Sutthiumporn, K.; Maneerung, T.; Kathiraser,
Y.; Kawi, S. Int. J. Hydrogen Energy., 2012,
37, 11195-11207.
Jahangiri, A.; Aghabozorg, H. R.;
Pahlavanzadeh, H. Int. J. Hydrogen Energy.,
2013, 38, 10407-10416.
5.
6.
7.
Zhang, W. D.; Liu, B. S.; Zhu, C.; Tian, Y. L.;
Appl. Catal. A: Gen., 2005, 292, 138-143.
Ruckenstein, E.; Wang, H. Y. Catal, Lett.,
2001, 73, 99-105.
Eltejaei, H.; Bozorgzadeh, H. R.; Towfighi, J.;
Omidkhah, M.R.;Rzari, M.;R.Zanganeh, R.Int.
J. Hydrogen Energy., 2012, 37, 4107-4118.
García-Diéguez, M.; Pieta, I. S.; Herrera, M.
C.; Larrubia, M. A.; Alemany, L. J. J. Catal.
2010., 270, 136–145.
18.
19.
20.
8.
9.
Urasaki, K.; Tokunaga, K.; Sekine, Y.;
Matsukata, M.; Kikuchi, E. Catal. Commun.,
2008, 9, 600-601.
Jahangiri,A.;Pahlavanzadeh,H.;Aghabozorg,
10.
Dejaidja, A.;Libs, S.;Kiennemann, A.;Barama,

1477
AGHABOZORGB et al., Orient. J. Chem., Vol. 34(3), 1469-1477 (2018)
H. R. Int. J. Hydrogen Energy., 2012, 37,
9977-9984.
Goldwasser, M. R.; Rivas, M. E.; Pietri,
E.; Perez-Zurita, M. S.; Cubeiro, M. L.;
Gingembre, L.;Leclercq, L.;Leclercq, G.Appl.
Catal., 2003, 225, 45-47.
Jahangiri,A.;Aghabozorg,H.R.;Pahlavanzadeh,
H.; J, Tow fighi, J. Int. J. Chem. React. Eng.,
2014, 12, 1–10.
Valderrama, G.;Kiennemann, A.;Goldwasser,
M. R. Catal. Today., 2008, 133, 142–148.
Catherine, B.D.;Gallego, G.A.S.;Mondragon,
F.; Barrault, J.; Tatibouet, J. M. Catal. Today.,
2005, 107, 474-480.
Zhongshan, Y.; Changjun, N.; Chunxi, Z.;
Diannan, G.;Shudong, W.; Yuming, X.;Akira,
O. Catal. Today., 2009, 146, 124–131.
Jun, K.W.;Roh, H.S.;Chary, K.V. Catal.Surv.
Asia., 2007, 11, 97–113.
Valderrmaa, G.;Goldwasser, M.R.;Navarro, C.
U.; Tatibouët, J. M.; Barrault,J.; Dupeyrat, C. B.;
Martinez, F. Catal.Today., 2005, 107, 785–791.
Supaporn,T.;Apichai,T.;Chairut, S.;Sarayut,Y.
Int. J. Hydrogen Energy., 2008, 33, 991-999.
Choque,V.;Ramírez, P.;Molyneux, D.;Homs,
N. Catal. Today., 2010, 149, 248–253.
Talaie, N.;Hossaini Sadr, M.; Aghabozorg, H.R.;
Zare, K. Orient. J. Chem., 2016, 32 (5). 304-315.
Pakhare, D.; Schwartz, V.; Abdelsayed, V.;
Haynes, D.;Shekhawat, D.;Poston, J.;Spivey,
J. J.Catal., 2014, 316, 78-92.
32.
Soongprasit,K.;Aht-Ong,D.;Sricharoenchaikul,
V.; Atong, D. Current Applied Physics., 2012,
12(2), 80-88.
Lim, H. S.; Kang, D.; Lee, J.W. Appl. Catal. B:
Invironmental., 2017, 202, 175-183.
Pakhare, D.; Spivey, J., Chem. Soc. Rev.,
2014, 43, 7813-7837.
Bushra, I.; Syed Tajammul, H.; Sohaib, A.
Chem. Ing. J., 2013, 219, 395-402.
Lucrédio, A. F.; Assaf, J.M.; Assaf, E. M. Appl.
Catal. A: Gen., 2011, 400, 156-165.
Barros, B.S.; Libs, S.; Melo, D. M. A.;
Kiennemann, A. Appl. Catal. A: Gen., 2010,
378(1), 69-75.
Li, J.; Li, J. G.; Zhang, Z.; Wu, X.; Liu, S.; Li,
X.;Sun, X.;Sakka,Y.Sci.Technol.Adv.Mater.,
2012, 13(3),235-250.
21.
22.
33.
34.
35.
36.
37.
23.
24.
25.
38.
26.
27.
39.
40.
41.
Liu, B.S.; Zgao, L.; Au, C.T. Appl. Catal. A:
Gen., 2002, 235, 193-206.
Kwak, J. H.; Lee, S. G.; Lee, S. H.; Park,Y. K.;
Sohn, J. M. Catal. Today., 2014, 232, 11-15.
Logvinovich, D.; Sheptyakov, D.; Bocher, L.;
weidenkaff, A. Solid State Sciences., 2009,
11(8), 1513-1519.
De Caprariis, B.; De Filippis, P.; Palma, V.;
Petrullo, A.;Ricca, A.;Ruocco, C.; Scarsella,
M. Appl. Catal. A: Gen., 2016, 517, 47-55.
Mohebbi, H.; Ebadzadeh, T.; Hesari, F.A.
Powder Technology., 2009, 188, 183-186.
28.
29.
30.
31.
42.
43.