Catalytic dehydrogenation of isobutane over ordered mesoporous Cr 2O3-Al2O3 composite oxides

Article abstract of DOI:10.1016/j.catcom.2013.02.011

A series of ordered mesoporous Cr₂O₃-Al ₂O₃ composite oxides synthesized via improved one-pot evaporation induced self-assembly strategy were investigated as the catalysts for catalytic dehydrogenation of isobutane. These mesoporous catalysts with good structural properties and thermal stability performed excellent catalytic properties. Besides, the effect of the ordered mesopore structure on improving catalytic properties was also studied. Compared with non-mesoporous catalyst, the current mesoporous catalyst could accommodate the gaseous reactant with more "accessible" active sites. Therefore, the present materials were considered as promising catalyst candidates for catalytic dehydrogenation of isobutane.

Full text of DOI:10.1016/j.catcom.2013.02.011

Catalysis Communications 35 (2013) 76–81
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Catalysis Communications
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Short Communication
Catalytic dehydrogenation of isobutane over ordered mesoporous
Cr2O3–Al2O3 composite oxides
Leilei Xu a,b, Zhonglai Wang a,b, Huanling Song a, Lingjun Chou a,c,
⁎
a
State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China
b
University of Chinese Academy of Sciences, Beijing 100049, PR China
c
Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of ordered mesoporous Cr2O3–Al2O3 composite oxides synthesized via improved one-pot evaporation
induced self-assembly strategy were investigated as the catalysts for catalytic dehydrogenation of isobutane.
These mesoporous catalysts with good structural properties and thermal stability performed excellent catalytic
properties. Besides, the effect of the ordered mesopore structure on improving catalytic properties was also
studied. Compared with non-mesoporous catalyst, the current mesoporous catalyst could accommodate the
gaseous reactant with more “accessible” active sites. Therefore, the present materials were considered as promising
catalyst candidates for catalytic dehydrogenation of isobutane.
Received 25 November 2012
Received in revised form 24 January 2013
Accepted 4 February 2013
Available online 14 February 2013
Keywords:
Catalytic dehydrogenation
Isobutane
© 2013 Elsevier B.V. All rights reserved.
Ordered mesopore
Cr2O3–Al2O3
Composite oxides
1. Introduction
reusability are main obstacles. Therefore, it is more practical to develop
Cr based catalysts with outstanding properties due to its high initial
In recent years, there has been increasing demand for light
alkenes, such as ethylene, propylene, and isobutene, which are exten-
sively utilized as the raw materials for polymer industry and other
commodity chemicals [1–3]. Further, isobutene is often utilized as
the basic building block for producing MTBE, which commonly acts
as the additive to lead-free gasoline to enhance its octane number
[4]. Fortunately, the catalytic dehydrogenation of isobutane process
could provide an attractive as well as inexpensive route for producing
isobutene [4–6]. In addition to this, another additional advantage of
this process is that it could provide low-cost hydrogen, which is a
greatly valuable feedstock for ammonia industry, petroleum refinery,
fuel cell, etc. [1]. However, this process is usually carried out at high
temperatures due to its intensely endothermic feature. Therefore, the
thermal cracking of isobutane and the following formation of coke
seem to be inevitable under this high temperature condition [3,7].
Thus, developing catalysts with high activity, selectivity as well as
excellent endurance are the present research focus.
activity. In order to achieve this goal, various strategies, including using
different preparation methods [3,13,14], introducing auxiliary agents
[15,16], employing various carriers [17–20], etc., have been widely used.
In this communication, a series of ordered mesoporous Cr2O3–Al2O3
composite oxides were facilely synthesized via one-pot evaporation
induced self-assembly strategy (EISA). The obtained materials with
excellent textural properties and good thermal stability were investigated
as the catalysts of catalytic dehydrogenation of isobutane. To the best of
our knowledge, there was almost no report on catalytic dehydrogenation
of isobutane over ordered mesoporous Cr2O3–Al2O3 composite oxides.
More details related with their catalytic properties would be described
specifically in the main text.
2. Experimental
Detailed description concerning the synthesis, characterization, and
catalytic property measurement of ordered mesoporous Cr2O3–Al2O3
composite oxides was presented in Supporting Information S1
Experimental.
As we know, both Pt and Cr based catalysts have been widely used for
alkane dehydrogenation [3–5,8–12]. Although, compared with Cr based
catalysts, the Pt based catalysts usually performed better resistance to-
wards coke and long-term catalytic stability, their higher cost and poorer
3. Results and discussion
3.1. XRD analysis
⁎
Corresponding author at: State Key Laboratory for Oxo Synthesis and Selective Oxidation,
Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR
China. Tel.: +86 931 4968066; fax: +86 931 4968129.
The small-angle XRD (SXRD) patterns exhibited in panel A of Fig. 1
(1) provided the evidence for the presence of ordered mesostructures
E-mail address: ljchou@licp.cas.cn (L. Chou).
1566-7367/$ – see front matter © 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.catcom.2013.02.011

L. Xu et al. / Catalysis Communications 35 (2013) 76–81
77
for OMA-xCr. As shown in the figure, each sample presented a strong
3.2. Nitrogen adsorption–desorption analysis
diffraction peak around 0.7° and another weak peak around 1.4°,
respectively. Therefore, a good mesoscopic order was successfully
maintained even after calcined at temperature as high as 700 °C,
revealing high thermal stability of the mesoporous structures of
Nitrogen adsorption–desorption isotherms for OMA-xCr samples
were displayed in Fig. 2 (1) A. All isotherms were attributable to
type IV with H1-shaped hysteresis loops, which were the typical fea-
tures for the presence of mesopores with cylindrical shape. Besides,
the pore size distributions of these samples were shown in Fig. 2
(1) B. For the adsorption isotherms with steep condensation steps,
the corresponding pore size distribution curves performed very
narrow distribution around 10.0 nm. In order to further investigate
the role of P123 template in forming uniform mesopores, the compar-
ative analysis between OMA-10Cr and NPA-10Cr was conducted and
the results were displayed in Fig. 2 (2). As shown in Fig. 2 (2) A,
different from OMA-10Cr with IV H1-shaped hysteresis loop, the
NPA-10Cr exhibited IV H3-shaped hysteresis loop, implying the
absence of uniform mesopores. Moreover, as shown in Fig. 2 (2) B,
dissimilar to OMA-10Cr with narrow pore size distribution, NPA-
10Cr performed greatly wide pore size distribution. These phenomena
once again demonstrated the crucial role of P123 template in shaping
ordered mesopore. Besides, the N2 adsorption–desorption isotherm
and pore size distribution curve of 10Cr/Al2O3 catalyst were also
depicted in Fig. 2 (2). Compared with OMA-10Cr, it also behaved IV
H3-shaped hysteresis loop and wide pore size distribution. It was
speculated that the mesopores existing among the 10Cr/Al2O3 might
be stemmed from the disordered accumulation of Al2O3 particles.
Moreover, the textural properties of above samples were summarized
in Table 1. It was noticeable that all the samples calcined at 700 °C were
provided with large BET specific surface areas up to 198.8 m2/g, big BJH
pore volumes up to 0.629 cm3/g, and average pore diameters around
10.0 nm. As a comparison, the NPA-10Cr possessed much smaller surface
area and pore volume.
OMA-xCr. Part
B of Fig. 1 (1) presented the wide-angle XRD
(WXRD) patterns of OMA-xCr. It was noticeable that all the samples
gave rise to γ phase alumina (JCPDS card no. 10-0425) diffraction
peaks with low intensity, illustrating that the crystallinity of the
OMA framework was not very good. However, the diffraction peaks
for Cr2O3 were absent when the Cr/Al ratio was lower than 7%,
demonstrating the high dispersion of Cr species among the
mesoporous framework. When the Cr/Al ratio increased from 7% to
15%, the Cr2O3 diffraction peaks (JCPDS card no. 84-1616) gradually
appeared. This indicated that the dispersion became poorer with the
increase of Cr containing.
Besides, the comparative analyses of XRD patterns for OMA-10Cr,
NPA-10Cr, and 10Cr/Al2O3 samples were also displayed in Fig. 1 (2).
As shown in the panel A, dissimilar to the OMA-10Cr, both 10Cr/
Al2O3 and NPA-10Cr performed not any diffraction peak in the small
angle region, suggesting the absence of ordered mesostructure.
Hence, the P123 template played an essential role in constructing
ordered mesoporous framework. Their WXRD patterns were also
presented in panel B of Fig. 1 (2). As described above, the OMA-
10Cr behaved remarkable Cr2O3 diffraction peaks; as a comparison,
the NPA-10Cr showed no obvious Cr2O3 diffraction peak. This
phenomenon implied that the presence of P123 template was in favor
of the formation of crystalline Cr2O3. As for 10Cr/Al2O3, it performed
characteristic diffraction peaks for both γ phase alumina and Cr2O3
species, which ought to be derived from γ-Al2O3 carrier and the thermal
decomposition of Cr(NO3)3·9H2O precursor, respectively.
Fig. 1. Small-angle XRD (A) and wide-angle XRD (B) patterns of Cr based catalysts: (1) OMA-xCr with different Cr loadings: (a) OMA-3Cr, (b) OMA-5Cr, (c) OMA-7Cr,
(d) OMA-10Cr, (e) OMA-15Cr; (2) comparative analyses of OMA-xCr, NPA-10Cr, and 10Cr/Al2O3 catalysts: (a) OMA-10Cr, (b) 10Cr/Al2O3, (c) NPA-10Cr.

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L. Xu et al. / Catalysis Communications 35 (2013) 76–81
Fig. 2. Isotherms (A) and pore size distributions (B) of Cr based catalysts: (1) OMA-xCr with different Cr loadings; (2) comparative analyses of OMA-xCr, NPA-10Cr, and 10Cr/Al2O3 catalysts.
3.3. TEM analysis
3.4. H2-TPR and XPS analyses
In order to further confirm the presence of ordered mesopores,
TEM characterization for OMA-xCr was carried out. OMA-3Cr, OMA-
7Cr, and OMA-10Cr samples were selected as representatives and
their TEM images were displayed in Fig. 3. For all the samples, the
alignment of cylindrical pores along [1 1 0] direction was distinctly
observed, which were` well consistent with the deduction based on
nitrogen adsorption–desorption analysis. Besides, the EDX measure-
ment of the ordered mesostructure region for OMA-10Cr was also
conducted and its profile was shown in Fig. 3 (e). The characteristic
peaks for Cr, Al, and O elements were clearly observed, suggesting
that all the metallic elements were successfully introduced into
ordered mesoporous framework.
The redox properties of the OMA-xCr catalysts were investigated
by H2-TPR and the resulting profiles were shown in Fig. 4 (1). It
could be clearly observed that the intensities of H2 consumption
peaks gradually increased with the augment in the Cr containing.
It was also noticeable that most of the samples behaved similar
profiles of hydrogen consumption in shapes regardless of Cr content,
specifically displaying one pronounced H2 reduction peak around
550 °C and one small shoulder peak around 300 °C. However, it was
reported in the previous literatures that the consumption of hydro-
gen was mainly caused by the reduction of Cr ions from +6 to +3
[10,16,21,22]. Therefore, these two reduction peaks should be
ascribed to the reduction of Cr6+ species in different coordination
environments. As for the peaks around 300 °C, they might be
assigned to the reduction of surface Cr6+. On the one hand, the unsat-
urated coordination of surface Cr6+ ions made them easier to reduce;
on the other hand, the surface Cr6+ ions could be more easily acces-
sible to H2 stream owing to their large surface areas and uniform
pore channels. As a result, they could be easily reduced in lower tem-
perature region. The reduction peaks at higher temperature region
around 550 °C might be ascribed to the reduction of bulk Cr6+ ions,
which had strong interaction with the mesoporous framework.
Most of the Cr atoms were inlayed among the matrix of ordered
mesoporous skeleton due to the current one-pot synthesis strategy,
accounting for the bigger reduction peaks at higher temperature
region.
Table 1
Textural properties of OMA-xCr, NPA-10Cr, and 10Cr/Al2O3 catalysts.
Samples
Specific
Pore
Average pore
diameter
(nm)
Isotherm
type
Surface
Cr3+/Cr6+
ratio
surface area
volume
(m2/g)
(cm3/g)
OMA-3Cr
OMA-5Cr
OMA-7Cr
OMA-10Cr
OMA-15Cr
NPA-10Cr
10Cr/Al2O3
189.0
199.7
198.8
191.0
158.3
13.1
0.528
0.620
0.576
0.629
0.473
0.126
0.372
9.91
11.3
10.6
11.9
11.4
–
IV H1
IV H1
IV H1
IV H1
IV H1
IV H3
IV H3
2.10
1.73
1.06
0.98
1.45
1.72
2.33
Furthermore, the H2-TPR profiles of NPA-10Cr and 10Cr/Al2O3
were also summarized in Fig. 4 (1). As for the NPA-10Cr, dissimilar
to OMA-10Cr, its reduction peak was not conspicuous, only displaying
155.8
–
Surface Cr3+/Cr6+ ratio is obtained by peak fitting of the Cr2P profiles.

L. Xu et al. / Catalysis Communications 35 (2013) 76–81
79
(a)
(b)
50 nm
50 nm
(c)
(d)
50 nm
50 nm
(e)
Fig. 3. TEM images of the OMA-xCr catalysts: (a) OMA-3Cr, (b) and (c) OMA-7Cr, (d) OMA-10Cr, (e) EDX measurement of OMA-10Cr.
a small uptake around 476 °C. The reason for this might be derived
from relatively smaller surface area of NPA-10Cr than that of
OMA-10Cr. As a result, it could not provide sufficient “accessible”
Cr6+ species for the H2 stream. As regards the supported 10Cr/Al2O3
catalyst, it only performed one reduction peak in low temperature
region around 453 °C, which was extremely common for Cr based
catalyst supported Al2O3 according to previous literatures [15,19,21].
Compared with the reduction peak of OMA-10Cr at higher temperature
region around 550 °C, the Cr6+ species could be reduced at lower
temperature for the present supported catalyst. Therefore, the interac-
tion between Cr2O3 species and γ-Al2O3 support for 10Cr/Al2O3 was
somewhat weaker than that for OMA-10Cr. This situation might be
caused by the different catalyst preparation methods, which had been
detailedly described in Supporting Information S1 Experimental.
Besides, the surface Cr species on OMA-xCr, NPA-10Cr, and 10Cr/Al2O3
catalysts were examined by XPS measurements. The XPS spectra of Cr2P
were shown in Fig. 4 (2). It was apparent to find that the curves were
identical in shapes and the intensities of the peaks gradually became
stronger with the increase of Cr/Al ratio from 3% to 15% for OMA-xCr
catalysts. Besides, the peaks around 577.3 eV and 579.9 eV for Cr2P3/2
could be observed over all the samples, which ought to be assigned to
Cr3+ and Cr6+, respectively, according to pioneer literatures [3,4,21].
As for the 10Cr/Al2O3 and NPA-10Cr catalysts, they performed similar
patterns to OMA-xCr, illustrating that the surface Cr species also
mainly existed in the form of Cr3+ and Cr6+. Besides, the exact sur-
face Cr3+/Cr6+ ratios for all the samples were calculated by peak fitting
of the Cr2P profiles and their results were summarized in Table 1. As
shown in the table, the Cr3+/Cr6+ ratio decreased from 2.10 to 0.98
when the Cr content increasing from 3% to 10% for OMA-xCr; however,
further augment in Cr containing up to 15% made the Cr3+/Cr6+ ratio
increase a lot. As for NPA-10Cr and 10Cr/Al2O3 catalysts, they performed
much bigger Cr3+/Cr6+ ratios than OMA-10Cr, although they possessed
identical Cr loading. The reason for these phenomena remained unclear
due to current level of cognition.
3.5. Catalytic performances
The catalytic performances of the OMA-xCr with different Cr
containing for catalytic dehydrogenation of isobutane reaction at dif-
ferent temperatures under given condition (GHSV=1500 mL/(g·h),
1 atm) were summarized in Table 2. As shown in the table, with the
reaction temperature elevated, the conversion of isobutane suffered
some increase, reflecting the endothermic feature of this reaction [3,7].
However, for most of the samples, the selectivity of isobutene suffered
some decline with the increase of the reaction temperature from
580 °C to 610 °C. The reason for this might be derived from the thermal
cracking of the isobutane and/or isobutene at higher temperature.
Besides, the relationship between the catalytic activity and Cr
containing also could be expressed in Table 2. With the augment in
Cr content, the conversion of isobutane as well as the yield of
isobutene initially increased rapidly and reached summit at 7% or
10% Cr/Al ratio in the temperature region investigated because of
the increase in active sites. But further increase of Cr/Al ratio up to
15% led some decline in isobutane conversion and isobutene yield.

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L. Xu et al. / Catalysis Communications 35 (2013) 76–81
10Cr, the OMA-10Cr behaved much larger surface area, bigger pore
volume, and more ordered pore channels. As a result, the mesoporous
catalyst could provide more “exposed” or “accessible” Cr active sites
for the gaseous feedstock, which finally accounted for the better catalytic
performance of mesoporous catalyst.
In addition to these, the comparison between mesoporous catalyst
and traditional industrial catalyst was also carried out. As well
known, Cr based catalyst supported Al2O3 carrier was usually used
as industrial catalyst for catalytic dehydrogenation of isobutane.
Therefore, OMA-10Cr and 10Cr/Al2O3 with identical Cr loading were
selected as representatives and their results were also summarized
in Table 2. It could be observed that the conversions of isobutane
over 10Cr/Al2O3 catalyst were higher than those over OMA-10Cr for
the reaction temperatures studied. But the selectivity to isobutene
over 10Cr/Al2O3 catalyst was inferior to that over OMA-10Cr.
It might be the strong Lewis acid sites over 10Cr/Al2O3 catalyst that
caused seriously thermal cracking of the isobutane and/or isobutene,
finally leading to low isobutene selectivity.
Finally, 300 min laboratory-scale stability tests (five dehydroge-
nation–regeneration cycles) were examined over OMA-10Cr and
10Cr/Al2O3 catalysts under specific reaction condition: 610 °C, GHSV=
1500 mL/(g·h), 1 atm. The experimental results were exhibited in
Fig. 5. As shown in Fig. 5 (1), the isobutane conversions over both cata-
lysts suffered some decline for each run (60 min), which was the com-
mon feature for Cr based catalysts due to the carbon deposition over
the active center. However, the catalytic stability over OMA-10Cr catalyst
was much better than that over 10Cr/Al2O3. Taken the first cycle
for example, the OMA-10Cr maintained ~67% of its initial activity; as
a comparison, 10Cr/Al2O3 only retained ~54% of its initial activity.
Further, compared with the original catalyst, the regenerated OMA-
10Cr performed similar or even higher isobutane conversion only
after
a simple heating treatment in flowing air; however, the
regenerated 10Cr/Al2O3 could not regain its original activity. After
five cycles, the initial activity over 10Cr/Al2O3 suffered great decline
from 63.7% for the first cycle to 56.3% for the fifth cycle. Besides, it was
noticeable in Fig. 5 (2) that for both catalysts, the selectivity to
isobutene only decreased slightly within each cycle and the value over
the regenerated catalyst was even a little higher than that over original
catalyst. But the isobutene selectivity over 10Cr/Al2O3 was always lower
than that over OMA-10Cr. Therefore, all the phenomena mentioned
above indicated that OMA-10Cr catalyst performed better catalytic
stability than 10Cr/Al2O3 catalyst.
Fig. 4. H2-TPR profiles (1) and XPS spectra (2) of OMA-xCr catalysts calcined at 700 °C:
(a) OMA-3Cr, (b) OMA-5Cr, (c) OMA-7Cr, (d) OMA-10Cr, (e) OMA-15Cr, (f) NPA-10Cr,
(g) 10Cr/Al2O3.
Its reason might derive from the agglomeration of Cr2O3 based on
XRD characterization in Fig. 1 (1) B, finally causing the decrease in
active sites.
In order to investigate the influence of ordered mesoporous struc-
ture on catalytic performance, OMA-10Cr and NPA-10Cr with and
without uniform mesopore were selected as the representatives and
their results were listed in Table 2. It was noticeable that both isobutane
conversion and isobutene selectivity of NPA-10Cr were all much lower
than those of OMA-10Cr, respectively, which might be attributed to the
difference in structural properties. Specifically, compared with NPA-
4. Conclusion
A series of ordered mesoporous Cr2O3–Al2O3 composite oxides
with various Cr content had been successfully prepared by improved
one-pot EISA method. The obtained materials utilized as the catalysts
for catalytic dehydrogenation of isobutane performed high catalytic
activity, selectivity, and excellent stability. Besides, it was also found
that the ordered mesoporous structure played a crucial role in
promoting the catalytic activity by providing more “accessible”
active sites for the gaseous reactant. Therefore, the present ordered
Table 2
Catalytic performances for dehydrogenation of isobutane over OMA-xCr, NPA-10Cr, and 10Cr/Al2O3 catalysts at different temperatures; reaction condition: GHSV=1500 mL/(g·h), 1 atm.
Samples
580 °C
585 °C
590 °C
600 °C
610 °C
Ci-C4H10
Si-C4H8
Ci-C4H10
Si-C4H8
Ci-C4H10
Si-C4H8
Ci-C4H10
Si-C4H8
Ci-C4H10
Si-C4H8
OMA-3Cr
OMA-5Cr
OMA-7Cr
OMA-10Cr
OMA-15Cr
NPA-10Cr
10Cr/Al2O3
34.7
37.0
41.8
39.2
30.9
10.0
51.9
91.7
92.6
90.6
91.6
92.2
71.3
87.9
34.9
35.6
46.4
42.7
35.9
12.7
55.6
91.6
91.6
92.1
92.2
92.4
75.4
87.8
35.2
44.9
46.2
46.6
34.4
14.9
57.4
89.1
92.8
92.5
91.8
92.5
86.4
86.7
42.2
44.2
47.0
48.1
31.1
14.8
59.2
88.4
93.2
92.0
91.5
91.2
86.9
86.2
42.8
46.1
48.6
51.2
29.5
22.6
63.7
87.6
90.3
88.6
89.6
86.2
89.8
84.6
Ci-C4H10 stands for the conversion of isobutane. Si-C4H8 stands for the selectivity of isobutene.

L. Xu et al. / Catalysis Communications 35 (2013) 76–81
81
activity and selectivity of targeted product would be presented in
our future work.
Acknowledgments
The authors sincerely acknowledge the financial support from the
National Basic Research Program of PR China (no. 2011CB201404) and
the National Natural Science Foundation of China (no. 21133011).
Appendix A. Supplementary data
Supplementary data to this article can be found online at http://
dx.doi.org/10.1016/j.catcom.2013.02.011.
References
[1] P. Sun, G. Siddiqi, M. Chi, A.T. Bell, Journal of Catalysis 274 (2010) 192–199.
[2] S. Sahebdelfar, P.M. Bijani, M. Saeedizad, F.T. Zangeneh, K. Ganji, Applied Catalysis
A: General 395 (2011) 107–113.
[3] D. Shee, A. Sayari, Applied Catalysis A: General 389 (2010) 155–164.
[4] F. Cavani, M. Koutyrev, F. Trifiro, A. Bartolini, D. Ghisletti, R. Iezzi, A. Santucci,
G. DelPiero, Journal of Catalysis 158 (1996) 236–250.
[5] S.M. Stagg, C.A. Querini, W.E. Alvarez, D.E. Resasco, Journal of Catalysis 168 (1997)
75–94.
[6] E. Novakova, N. Winterton, K. Jarosch, J. Brophy, Catalysis Communications 6
(2005) 586–590.
[7] Y. Zhang, Y. Zhou, J. Shi, X. Sheng, Y. Duan, S. Zhou, Z. Zhang, Fuel Processing
Technology 96 (2012) 220–227.
[8] R.D. Cortright, J.A. Dumesic, Journal of Catalysis 148 (1994) 771–778.
[9] R.D. Cortright, J.M. Hill, J.A. Dumesic, Catalysis Today 55 (2000) 213–223.
[10] A. Hakuli, M.E. Harlin, L.B. Backman, A.O.I. Krause, Journal of Catalysis 184 (1999)
349–356.
[11] Z. Nawaz, X. Tang, Q. Zhang, D. Wang, W. Fei, Catalysis Communications 10
(2009) 1925–1930.
[12] Y. Zhang, Y. Zhou, Y. Li, Y. Wang, Y. Xu, P. Wu, Catalysis Communications 8 (2007)
1009–1016.
[13] A. Hakuli, A. Kytokivi, A.O.I. Krause, Applied Catalysis A: General 190 (2000)
219–232.
[14] S.M.K. Airaksinen, A.O.I. Krause, Industrial and Engineering Chemistry Research
44 (2005) 3862–3868.
[15] M. Cherian, R. Gupta, M.S. Rao, G. Deo, Catalysis Letters 86 (2003) 179–189.
[16] E. Rombi, M.G. Cutrufello, V. Solinas, S. De Rossi, G. Ferraris, A. Pistone, Applied
Catalysis A: General 251 (2003) 255–266.
[17] M. Hoang, J.F. Mathews, K.C. Pratt, Journal of Catalysis 171 (1997) 320–324.
[18] S. De Rossi, M.P. Casaletto, G. Ferraris, A. Cimino, G. Minelli, Applied Catalysis A:
General 167 (1998) 257–270.
[19] S.B. Wang, K. Murata, T. Hayakawa, S. Hamakawa, K. Suzuki, Applied Catalysis A:
General 196 (2000) 1–8.
Fig. 5. Catalytic performances for dehydrogenation of isobutane over OMA-10Cr and
10Cr/Al2O3 catalysts versus time on stream: (1) isobutane conversion; (2) isobutene
selectivity. Reaction condition: T=610 °C, GHSV=1500 mL/(g·h), 1 atm; spent catalyst
for each cycle was regenerated at 700 °C in flowing of air (40 mL/min) for 30 min.
[20] S.T. Korhonen, S.M.K. Airaksinen, M.A. Banares, A.O.I. Krause, Applied Catalysis A:
General 333 (2007) 30–41.
[21] B. Grzybowska, J. Sloczynski, R. Grabowski, K. Wcislo, A. Kozlowska, J. Stoch, J. Zielinski,
Journal of Catalysis 178 (1998) 687–700.
mesoporous Cr2O3–Al2O3 composite oxides could be considered as a
series of promising catalysts for dehydrogenation of isobutane
reaction. Further studies related with further improving catalytic
[22] J.M. Kanervo, A.O.I. Krause, Journal of Catalysis 207 (2002) 57–65.