Synthesis and properties of MFI zeolites with microporous, mesoporous and macroporous hierarchical structures by a gel-casting technique

Article abstract of DOI:10.1039/c5nj03387j

The comparatively small micropore dimensions of bulk ZSM-5 zeolites often limit both the adsorption and catalytic conversion of large organic molecules. Here, we report that ZSM-5 zeolites were prepared by a gel-casting technique with microporous, mesoporous and macroporous hierarchical structures. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, temperature-programmed-desorption of ammonia (TPD-NH₃) and Fourier transform infrared spectroscopy (FTIR) measurements. The hierarchical structured ZSM-5 zeolites were used to carry out catalytic cracking of 1,3,5-triisopropyl benzene and n-hexadecane. The results show that, compared with traditional ZSM-5, Beta or Al-MCM-41, this modified ZSM-5 displayed preferable catalytic activity and selectivity.

Full text of DOI:10.1039/c5nj03387j

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DOI: 10.1039/C5NJ03387J
NJC
PAPER
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The Synthesis and Properties of MFI Zeolites with Microporous,
Mesoporous and Macroporous Hierarchical structures by a Gel-
casting Technique
a
a
a
a
a
b
Ying Wang , Runwei Wang , Diou Xu , Chuanyin Sun , Ling Ni ，Weiwei Fu ,
a
a
a
a
Shangjing Zeng , Shang Jiang , Zongtao Zhang* and Shilun Qiu*
The comparatively small micropore dimensions of bulk ZSM-5 zeolites often limit both the adsorption and the catalytic
conversion of large organic molecules. Here, we report that the ZSM-5 zeolites were prepared by a gel-casting technique
with microporous, mesoporous and macroporous hierarchical structure. The as-prepared samples were characterized by X-
ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), nitrogen adsorption,
Temperature-programmed-desorption of ammonia (TPD-NH3) and Fourier Transform Infrared Spectroscopy (FTIR)
measurements. The hierarchical structured ZSM-5 zeolites were used to carry out catalytic cracking reaction of 1, 3, 5 -
isopropyl benzene and n-hexadecane. Data shows that compared with traditional ZSM-5, Beta or Al-MCM-41, this modified
ZSM-5 displayed preferably catalytic activity and selectivity.
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
www.rsc.org/
ZSM-5 zeolites fail to catalyze larger molecules. Because of their
Introduction
diffusion limitations in the microporous channels and carbon
deposition in the porous systems, ZSM-5 zeolites have severe
catalyst deactivation.10 As we all know, construction of ZSM-5
In general, zeolites are crystalline aluminosilicates with well-
defined porous structures in which water and other types of
materials with different levels of pores can improve reaction
efficiency and minimize channel blocking.11-14 It may be a good
1
molecules can pass through. Zeolites are widely used in the fields of
choice to solve the problems.
catalysis, adsorption and separation. However, most of these pores
are smaller than 2 nm and the molecules transferring to the active
sites locating inside these micropores can be slowed down by
diffusion constraints. When different sizes of pores, such as
mesoporous or macroporous crystals are present, it is possible to
facilitate the transport of bulky molecules in these materials. 2 −7
Producing gasoline by catalytic cracking of petroleum began in
about 1912. The early pioneering work was carried out by Eugene
15
Houdry . Catalytic cracking cracks valueless high molecular weight
hydrocarbons into more valuable by-products (low molecular weight)
like gasoline, LPG Diesel along with very important petrochemical
feedstock like propylene, C4 gases like isobutylene, Isobutane,
butane and butene. According to the IEA's World Energy Outlook,
global energy demand will grow more than a third over the period to
Among the various of natural and synthetic zeolites, ZSM-5
zeolites are widely used in petrochemistry and chemical industry for
series of reactions involving cracking reaction and alkylation
reaction.8 The penetrating and crossing microporous networks,
possess straight channels along the b axis (0.53 nm × 0.56 nm) and
zigzag channels along the a axis (0.51 nm × 0.55 nm), this structure
endows the ZSM-5 with high shape and size selectivity.9 Hence,
2
035, 60% of the increase come from rising living standard of China,
India and the Middle East.16 The impending challenge we are facing
with is how to fully crack the heavy residue oil to various valuable
chemical products. The pores of the traditional catalyst are too small
to prevent the crossing of the large molecules (crude oil and residue),
which directly hinders the cracking reactions. We put forward the
research basing on a series of environmental and energy problems.
To facilitate reactant molecules and products easily to transport to
the active sites, efforts have been made to obtain hierarchical porous
zeolite materials with micro-, meso- and macro-porosity.17-26
a.
College of Chemistry and State Key Laboratory of Inorganic Synthesis and
Preparative Chemistry, Jilin University, Changchun 130012, China.
E-mail: sqiu@jlu.edu.cn; Fax: +86 431 85168115; Tel: +86 431 85168115
zzhang@jlu.edu.cn;Fax: +86 431 85168115; Tel: +86 431 85168115
b.
Experimental Center of Shenyang Normal University, Liaoning Shenyang 110034,
P. R. China
†
Supplementary Information (ESI) available: TG-DTA curves of ZSM-5, A-ZSM-5,
G-ZSM-5and calcined G-ZSM-5 and Catalytic Activities in Cracking of 1, 3, 5-
Triisopropylbenzene and Hexane on Various Catalysts. See DOI:
1
0.1039/x0xx00000x
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3
2
MCM-41 . Further, the gel-casting method makes G-ZSM-5
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possible as technical catalysts. 33.34
DOI: 10.1039/C5NJ03387J
Results and discussion
C
B
A
Hierarchical porous ZSM-5 zeolites were synthesized by
hydrothermal synthesis, alkaline-media erosion (A-ZSM-5), gel-
casting method and calcined under appropriate temperature(G-ZSM-
5
). Moreover, the G-ZSM-5 zeolite with excellent properties of
catalytic cracking 1, 3, 5- triisopropylbenzene and n-hexadecane
were fabricated by this simple method.
Structural properties
5
10
15
20
25
30
35
40
o
2( )
The XRD patterns of all of the samples are shown in Figure 1,
initial ZSM-5, treated with alkaline (A-ZSM-5) and Gel-casting
sample (G-ZSM-5), respectively. Figure 1A shows the X-ray
diffraction (XRD) pattern of the as-synthesized initial ZSM-5,
exhibiting the typical peaks associated with MFI-type structure with
ordered micropores. In Figure 1B, the relative intensities of the
typical peak decrease after treating with concentrated alkaline
solution. Such decrease can be explained by a partial removal of
microporous structure to form some irregular mesopores, these
differences also present in Figure 1A and Figure 1C. In Figure 1B
and 1C, the diffraction peaks well corresponding to zeolite MFI
structure in the wide-angle XRD pattern, indicating that all as
synthesized zeolites are still preserved with ordered micropores.
Figure 1. XRD patterns of (A) initial ZSM-5, (B) the ZSM-5 After
treating with alkaline (A-ZSM-5), and (C) Gel-casting sample (G-
ZSM-5).
Hierarchical zeolites are generally fabricated by post-synthesis
treatments, template self-assembly, etching in acid or base solution
and so on. Janssen et al.27 presented an idea on the generation of
mesopores in hierarchical zeolites that selects carbon as a template
during the synthesis. Wang et al.28 and Zheng et al. prepared meso-
ZSM-5 zeolites during hydrothermal treatment using Beta and
Mordenite zeolites as Si/Al source, respectively. Abelló et al.30
synthesized hierarchical materials by desilication of ZSM-5 zeolites.
However, the conversion processes are extremely slow and the final
structures are usually composites of the starting materials and the
zeolite with non-uniform microstructure.31 In this paper, hierarchical
structured ZSM-5 zeolites with micropores, mesopores and
macropores were prepared using a gel-casting technique. The
hierarchical structured ZSM-5 zeolites were used to carry out
cracking reaction of n-hexadecane and showed higher catalytic
activity and selectivity than that of traditional ZSM-5, Beta, Al-
29
The G-ZSM-5 sample photographs were shown in Figure 2A. The
synthetic process is monitored by SEM techniques. According to the
SEM images Figure 2B, all of the initial precursors crystals exhibit
spheres-like morphology with smooth surface, and the average
crystal surface size of individual spheres is about 150-200 nm. The
mesopores are created with random morphology (Figure 2C), as
evidenced by the decrease relative intensity of diffraction peaks in
Figure 2. Photograph, SEM images of the sample (A) a photograph of the final sample (taken with a digital camera), (B) ZSM-5, (C) A-
ZSM-5, and (D)G-ZSM-5.
2
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Figure 3. Transmission electron microscopy (TEM) images of ZSM-5 which were treated with gel-casting method(A), (B) and (C) the
magnification of a region in A for clarity.
ascribed to MFI structure typical double five membered rings of
the wide-angle XRD pattern (Figure 1B) due to the erosion in
T-O-T (T = Si or Al), and the 454 cm-1 band corresponded to
alkaline media. The changes in morphology and crystallinity of
characteristic bending vibration of T-O. In addition, The IR
the mesoporous walls are observed by TEM (Figure 3). The
products obtained over Gel-casting method (Figure2D) retain the
well-defined microporous structures and irregular mesopores. On
the other hand, random macropores can be clearly seen caused by
organic polymers.
–1
peaks at 1224, 1095 and 802 cm , corresponded to characteristic
peaks of the ZSM-5 zeolite frame vibration peak.35 The band
observed at 1224 and 1095 cm–1 is assigned to asymmetric
stretching vibration of internal tetrahedron structure of ZSM-5
zeolite, and the band at 802 cm–1 is similar to symmetric
stretching vibration of internal tetrahedron structure. In the
Figure 4 there is an additional band of 3446 cm–1 which is
TEM (Figure 3) images demonstrate that the hollow structure
has well defined hexagon shape and uniform size (150 nm). The
TEM image of the zeolite crystal (Figure 3A) displays the
mesopores as brighter features pervading the crystal, yet without
clear indication of their shapes and sizes, since they are irregular.
It is note worthy that the microporous wall can be clearly
observed from the high resolution TEM (HRTEM) image (Figure
assigned to O-H of zeolite ZSM-5 or water adsorbents. The FTIR
spectrum of A-ZSM-5 is similar to that of ZSM-5, which
indicates that the structure of ZSM-5 zeolite is not broken by
alkaline erosion. However the band at 1095 cm–1 broadened,
which should be resulted from low crystallization, due to the
consumption of Si in the process of alkaline post-synthesis. As
3
C). Due to the grinding and ultrasonic of the samples, the
expected, peaks corresponding to the C-C vibration mode of
organic polymer are observed in the region of 1421cm-1 for as-
intercrystal macropores can not be observed directly from the
TEM images.
made G-ZSM-5(C), while no IR signal corresponding to the
polymer is detected after calcination at 550ºC. Moreover, The IR
Surface properties
-1
peak at 1421cm is quite weak due to the low percentage of
polymer in the sample. However after calcination, the typical
band at 1095 cm–1 sharpened proving the fact that the crystal
The crystallinity of the samples is assessed by the intensity
ratio of the vibration band at 550 cm-1 over that at 450 cm-1 in the
FTIR spectroscopy. The existence of the 550 cm-1 band can be
becomes smaller and more perfect.
2
Figure 5 shows the N adsorption–desorption isotherms of the
resulting ZSM-5 samples. All of the samples exhibit the
characteristic Type I adsorption isotherms with a steep increase
-
6
in the curve at a relative pressure of 10 <P/P0<0.01, which is
due to the filling of micropores. While a small uptake near
saturation pressure in the isotherms of the resulting materials are
observed, which indicates that secondary mesopores or
macropores are present in the crystals. Apart from the micropores
with diameters of about 0.55 nm (Figure inset), which is typical
for ZSM-5, samples A-ZSM-5 (Figure 5B) and G-ZSM-5 (Figure
5
C) exhibit the type-IV isotherms, and the large hysteresis loops
in the region 0.40<P/P <0.98 are observed due to the capillary
0
condensation in the mesopores (Figure 5) which may be of
importance for mass transport. Meanwhile, the pore size
distribution in 2–100 nm also demonstrate the existence of
hierarchical porosity in samples A-ZSM-5 and G-ZSM-5 (Figure
Figure 4. FTIR spectra of (A) ZSM-5, (B)A-ZSM-5, (C) G-
ZSM-5 and (D) calcined G-ZSM-5.
5
inset). The detailed surface area ,Si/Al ratio and pore volume
data are summarized in Table 1. Notably, the hierarchical sample
2
A-ZSM-5 displays significantly increased surface (394.15 m / g)
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Figure 5. Nitrogen adsorption and desorption isotherm and the microporous and mesoporous distribution for
A)ZSM-5, (B) A-ZSM-5, and (C) G-ZSM-5
(
Figure 6. Argon adsorption and desorption isotherm and the microporous and mesoporous distribution for
A) ZSM-5, (B) A-ZSM-5, and (C) G-ZSM-5
polymers. Argon adsorption - desorption isotherms is as same as N
(
2
adsorption - desorption isotherm (Figure 6). Compared with
nitrogen sorption, it is better to use argon sorption to measure
micropores (Figure 6 inset). This is because argon is inert gas and it
has little effect on solid surface. The temperature of liquid argon is
higher than nitrogen and it is easier to meet the equilibrium time.
Argon gas molecular diameter and saturated vapor pressure is low,
which can detect a larger range of diameter of porous, so it is
3
and mesopore volume (0.9451 cm /g) as compared with the
conventional microporous ZSM-5 due to the alkaline erosion with
5
0% Si/Al ratio reduction. In accordance with the SEM and TEM
observations, there are two different levels of pores existing in the
hierarchical G-ZSM-5 samples, that is, micrometer sized pores (ca.
1
µm) corresponding to the line channals left by organic moleculars
and nanometer-sized mesopores (ca. 40 nm) resulted from a small
part of framework silicon lost during the NaOH treatment.
Compared with A-ZSM-5, a slightly lower uptake for G-ZSM-5 is
expected due to the more compact nanocrystals by adding organic
reasonable to get a higher result of argon sorption compared with
nitrogen sorption.36 But the actual results of A-ZSM-5 and G-ZSM-
5
are different from the theoretical value, which may be causede by
the varieties of the porous materials (Table 1).
4
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Table 1. Si/Al ratio and derived parameters obtained from the N
2
and Ar physisorption isotherm
sample
aBET
pore vol,
bSi/Al ratio
BET
t-Plot
micropore
volume,
(N2),
t-Plot
t-Plot
external
surface
t-Plot
external
surface
3
surface
cm /g
surface
micropore
volume,
area, (N2)
area, (Ar)
2
2
2
m /g
m /g
(Ar), cm /g
area, (N2)
area, (Ar)
2
2
2
cm /g
m /g
m /g
ZSM-5
A-ZSM-5
G-ZSM-5
358.25
394.15
382.27
0.38
0.95
0.80
63.62
38.30
38.99
398.10
338.01
330.11
0.09
0.09
0.09
0.13
0.10
0.10
171.45
189.18
148.02
100.16
106.87
97.839
a
The specific surface area calculated using the BET equation.
Si/Al ratio calculated from the ICP.
b
whereas the peak area indicates the acidic concentration of the
samples. All the samples show two desorption peaks: the first peak
in the range of near 200 ºC corresponds to weak acid sites, which is
attributed to T–OH (T = Si, P, Al) hydroxyl groups; the second peak
at high temperatures in the range of 380–410 ºC, corresponds to
strong acid sites.38 As indicated in Figure 7, the strong acid strength
of samples ZSM-5, A-ZSM-5 and G-ZSM-5 are similar, while the
concentration of weak acid sites gradually increases with the
decrease of the silicon contents in these nano ZSM-5 samples.
Finally, for G-ZSM-5, the peak at about 720 ºC can be ascribed to
stronger acid sites. From the conversion of hexane cracking in
Supplementary Table 2S, G-ZSM-5 has more Bronsted acid sites
than conventional ZSM-5 and MCM-41.
Catalytic cracking activities of 1, 3, 5 triisopropylbenzene over
various catalysts are given in Supplementary Table 1S. HZSM-5 is
Figure 7. Temperature - programmed desorption of ammonia (NH3-
TPD) curves for various samples of (A) ZSM-5, (B) A-ZSM-5, and
almost inactive due to its relatively small pore size and the large
diameter of the molecules to be cracked.29 HMCM-41 shows high
(C) G-ZSM-5.
activity under 400 ºC. However, it is completely loses activity after
treatment in boiling water for 6 h or at 600 ºC for 2 h.45 Under 240
ºC, the conversion of the 1, 3, 5-triisopropylbenzene has a sharp
decrease, attributing to the cracking temperature below its boiling
point, and the liquid molecules cannot be completely gasified. In
Thermal and Catalytic properties.
Supplementary Figure S1 shows TG/DTA curves comparison of the addition, the yield of propylene in experiment is lower than that in
four catalysts. A-ZSM-5, G-ZSM-5 and calcined G-ZSM-5 exhibit theory, which may ascribe to the coke forming. G-ZSM-5 with
similar loss patterns from room temperature to 300 ºC which is the micro-, meso- and macro-porous system exhibited catalytic activity
typical of ZSM-5, attributed to the loss of adsorbed water. At 320 ºC as high as that of HMCM-41 under 320 ºC. The catalytic cracking
to 420 ºC important differences are observed, and the hierarchical conversion of n-hexadecane remained the same for long cycle life
porous G-ZSM-5 samples displays more weight loss, the results vary more than 30 times, indicating G-ZSM-5 showed stable catalytic
depending on the organic polymers degradation. Until 800 ºC, the properties. G-ZSM-5 shows the longest catalyst lifetimes of the
overall TG/DTA profiles do not show significant weight loss catalysts studied and higher selectivity of
(
around 1 wt%), proving the high thermal stability of G-ZSM-5
compared with ZSM-5. The acidity of the calcined samples is
evaluated by NH -TPD measurements and the profiles are shown in
3
Figure 7. The desorption temperature indicate the acidic strength,
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Table 2. Catalytic Activities in Cracking of n-hexadecane on Various Catalysts
catalyst
temperature
conversion,
%
Selectivity,%
C8
℃
C1-C4
0.24
5.65
1.3
C5-C7
6.35
C9-C11
13.98
C12-C15
3.27
Beta
360
320
360
320
360
360
250
280
320
360
42.58
2.53
34.7
0.95
2
96.5
Beta
57.08
80.5
16.94
18.2
ZSM-5
ZSM-5
3.47
13.7
10.30
70.86
25.67
80.9
MCM-41
SBA-15
G-ZSM-5
G-ZSM-5
G-ZSM-5
G-ZSM-5
2.0
3.4
1.6
0.19
11.1
2.79
0.90
0.31
88.9
3.58
88.30
0.70
69.9
89.7
98.5
2.53
0.31
0.20
73.37
97.47
98.7
17.73
2.22
0.97
0.04
0.09
a
The conversion was calculation by internal reference method.
b
Selectivity=the area of the target product/all the area of the product.
propylene, and suggest that it is a good candidate catalyst for reaction temperature is lower than its boiling point , and the
industrial cracking of petroleum.
conversion approaches zero.
To further demonstrate the superiority in catalytic application,
The transportation of 1, 3, 5-triisopropylbenzene is heavily
catalytic tests of n-hexadecane conversion were carried out over our hindered by the microporous structure of traditional ZSM-5 and Beta,
catalysts, a model compound of heavier hydrocarbons. Catalytic through the micropores providing unique activity in cracking 1, 3, 5-
cracking of n-hexadecane (Table 2) shows that G-ZSM-5 exhibits a triisopropylbenzene. Hence, the conversion over that traditional
higher activity than that of HZSM-5 and Beta at 360 ºC. The zeolites is much lower than that of mesoporous materials, such as H-
experimental results show that the conversion of n-hexadecane are MCM-41. The hierarchical G-ZSM-5 zeolites with micro-, meso-
1
.6 and 2 over SBA-15 and MCM-41 respectively, which further and macroporous structures completely overcome the delivery
indicate the presence of mesopores is not the only reason for G- problems of traditional zeolites, and the conversion on G-ZSM-5 is
ZSM-5. HZSM-5 and Beta exhibit a lower conversion due to their as high as H-MCM-41. The cracking reaction of 1, 3, 5-
relatively small pore size, and the catalytic cracking of n-hexadecane triisopropylbenzene can occur on weak acid sites, and H-MCM-41
just takes place at the surface of the catalysts. But the conversion of has a relatively high conversion. However, the cracking of n-
n-hexadecane on mesoporous materials (MCM-41 and SBA-15) is hexadecane can only take place on strong acid sites, thus, traditional
close to zero which may be related to the strong acidity requirements mesoporous materials, such as H-MCM-41 and SBA-15 fail to
for this reactive feedstock. Moreover, the G-ZSM-5 catalyst shows perform well. The conversions on ordinary zeolites display relatively
the highest catalytic activity among these catalysts and better high, attributing to n-hexadecane with molecular chain conformation
thermal stability. The various temperature (Table 2) are having more freedom into the micropore under high temperature.
summarized with G-ZSM-5, ZSM-5 and Beta, and the However, the chain flexibility of n-hexadecath decreases once the
conversions reduce with the temperature decrease, but the reaction temperature lower than 360 ºC, which directly reduces the
reduction degree of G-ZSM-5 is smaller than others, proving coke transporting efficiency, directly resulting to the conversion decreased.
formation over the G-ZSM-5 catalyst is not significantly obvious, On the contrary, mesopores and macropores within the G-ZSM-5 are
further indicating higher catalyst stability as the result of its much larger than the molecular size of n-hexadecane. Although
enhanced porosity. It can be widely used in the cracking reaction under a lower temperature, zeolites G-ZSM-5 containing both micro-
of n-hexadecane under low temperature. Under 250 ºC, the and meso- macropores, still shows efficient mass-transport property.
6
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Trimodal Porosity facilitate mass transfer from the surface of the 2. Synthesis.
zeolite crystal followed by transport in small mesopores, finally
allowing diffusion into short micropores where catalysis takes place.
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Nanoscale zeolite ZSM-5 with size of 100-200 nm as the starting
Additionally, the acid sites of G-ZSM-5 have been remarkably
increased. Hence ,the typically synthesized G-ZSM-5 with different
material was hydrothermally synthesized according to a reported
37
method . The mole ratios of the materials were Al
2
O
3
/ SiO
O=1.0 / 217 / 128 / 3.75 / 4496.The resulted
powders were calcined at 550 ºC for 10h with a heating rate of 1 ºC
min to burn off the structure-directing agent TPAOH. The ZSM-5
2
/
levels pores shows absolute superiority in catalysis cracking large TPAOH / Na
2 2
O / H
reactants and products.
/
crystals with the size of 100-200 nm were obtained.Then the
prepared ZSM-5 was stirred in NaOH (0.2 M) for an hour at 90 ºC or
Conclusions
2
0s under microwave condition. The reaction was quenched by
soaking in an ice-water bath to room temperature. The solid product
was obtained by centrifugation and dried at 100 ºC.Then we used
gel-casting method to obtain the macroporous precursor. Organic
Hierarchical structured ZSM-5 zeolites with microporous,
mesoporous and macroporous systems were synthesized by using a
gel-casting technique. The G-ZSM-5 possessed a relatively large monomer acrylamide (AM) was dissolved in the water, crosslinker N,
2
surface area of 382.27m /g and exhibited good thermal stability and N-methylenebisacrylamide (MBAM) was added with stirring for 30
minutes, then the prepared ZSM-5 with hollow structure was added
high acidity. For the cracking of n-hexadecane, G-ZSM-5 displayed
into the solution with strong agitation for 36 hours, followed by
good catalytic properties with high activity and selectivity and long
adding initiator ammonium persulfate. The composition weight ratio
catalyst lifetime, when compared to the traditional ZSM-5 , Beta, Al-
4 2 2 8
is ((5–10) AM/(0.05–0.1) MBAM/(0.01–0.025) (NH ) S O /(90–95)
MCM-41. G-ZSM-5 materials, combination of micropore, mesopore
and macropore had advantageous situations for the easy accessibility
silicalite solid. Until a homogeneous solution was obtained, the
whole suspension was ultra-sonicated for 5–10 minutes to ensure
to all the acid sites and reducing the formation of coke precursor good homogeneity. The gel-casting of the resulting colloidal
with poor diffusion efficiency highly, additionally, the macroscopic suspension was carried out in a home-made mold (Centrifuge tube),
sealed statically at 60 ºC for 6 hours until the organic monomer in
feature and the level of pores can be controlled, so the materials
the suspension were polymerized, then dried at 60 ºC for 2–3 days
and further dried at 100 ºC overnight. Before drying, the suspension-
filled mold was hand-shaken for a few minutes to release air bubbles.
would widely used in residue fcc and hydrocracking macromolecules
reactions.
After drying, the tubular gel-casting sample was sintered under air at
a heating rate of 1 ºC/ min up to 500 ºC, and kept it for 8 h to burn
Experimental
off the organic polymer, for sintering together the silicalite
nanocrystals through condensation cross-linking of the surface
4
0-41
silanol groups of nanocrystals.
The fabrication process of G-
1
. Materials
ZSM-5 was illustrated in Figure 8. Since the suspension with
monomer, crosslinker, and initiator had low viscosity and good
fluidity, it can be easily transferred into the mold. Once the
Tetrapropylammonium Hydroxide (TPAOH, 25wt
%
aqueous
2
4
solution) Tetraethyoxysilane (TEOS), sodium hydroxide (NaOH),
Aluminium isopropoxide, N, N-methylenebisacrylamide, ammonium
temperature increased to 60 º C, the monomers in the suspension
were quickly polymerized and crosslinked freeradically into an
persulfate ((NH
4
)
2
S
2
O
8
), Ammonium nitrate (NH
4
NO
3
), acrylamide
42-44
elastic hydrogel.
A highly crosslinked polyacrylamide hydrogel
(
CH NCHCONH ). All chemicals were commercial samples from obtained was expected to link with silicalite nanocrystals because of
2
2
Aldrich and used without further purification.
2
the interaction of the surface silanol groups and -NH groups. The
solidified suspension (a gel-cast) was mechanically strong and easily
removed from the mold.
3
. Characterizations.
X-ray diffraction (XRD) patterns were obtained with a Rigaku
D/Max-2550 diffractometer using Cu Kα radiation ( λ= 1.5418 Å)
operated at 50 kV and 200 mA with the 2θ scanning speed of 10
(°)/min between 4°and 40°. Scanning electron microscopy (SEM)
was performed on a Hitachi JSM-6700F field emission scanning
electron microscope with an accelerating voltage of 50 KV.
Transmission electron microscopy (TEM) images were recorded on
a JEOL JSM-2010F field emission transmission electron microscope
operated at 300 kV. The nitrogen isotherms were measured on a
Micromeritics ASAP 2010 sorptometer at 77K. The samples were
degassed at 200 ºC for 8 h before measurement to desorb moisture
adsorbed on the surface and inside the porous networks. Surface
areas and pore structures were achieved from Brunauer–Emmett–
Teller (BET) method. The pore-size distribution for mesopores was
calculated by using the Barrett-Joyner-Halenda (BJH) model.45
Figure 8. Schematic representation of the gel-casting forming
process for a Plastic tube. The colloidal suspension consists of
molecular sieve and organic monomer (AM), crosslinker (MBAM),
4 2 2 8
and initiator (NH ) S O .
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NJC
Paper
Adsorption and desorption isotherms for Ar at 87.3 K were recorded
with a Micromeritics ASAP 2010 sorptometer. Before measure,
sample was out gassed at 573 for 6 h. The micropore volume were
Acknowledgements.
View Article Online
DOI: 10.1039/C5NJ03387J
This work is supported by the National Science Foundation Project
of China (21390394, 91022030 and 20971052), and the New
Century Outstanding Scholar Supporting Program.
2
derived preferably using the t-plot (N and Ar) methods, while the
mesopore volume were derived by the external surface area by the t-
plot. The catalytic cracking reactions of Hexane was carried out
according to the following conditions: mass of the catalyst was 0.05
g with 20-40 mesh; reaction temperature was under temperature
Notes and references
4
00℃ (no thermal cracking); and the ratio of Hexane to the catalyst
was 0.4 μL/0.05 g. Nitrogen was used as the carrier gas at a flow
rate of 83mL/min, under the atmospheric pressure of 0.1MPa.
Differential thermal analysis (DTA) and thermogravimetric analysis
1
.H. Manzano, L. Gartzia-Rivero, J. Bañuelos and I. López-
Arbeloa, J. Phys. Chem. C, 2013, 117, 13331; M. Veiga-
Gutiérrez, M. Woerdemann, E. Prasetyanto, C. Denz and L. De
Cola, Adv. Mater., 2012, 24, 5199.
(TG) were performed on NETZSCH STA 449C between room
temperature and 800℃ at a rising rate of 10℃/min. The Si/Al molar
ratio of samples were determined by induced coupled plasma
emission spectrum analyzer (ICP). Temperature-programmed-
2
3
.M. Hartmann, Angew. Chem. Int. Ed., 2004, 43, 5880.
.J. Perez-Ramírez, C. H. Christensen, K. Egeblad, C. H.
Christensen and J. C. Groen, Chem. Soc. Rev., 2008, 37, 2530.
.I. L. C. Buurmans, J. Ruiz-Martínez, W. V. Knowles, D. van der
Beek, J. A. Bergwerff, E. T. C. Vogt and B. M. Nat. Weckhuysen,
Chem, 2011, 3, 862.
3
desorption of ammonia (TPD-NH ) curves were recorded on
automated chemisorption (Micromeritics AutoChem II 2920) in the
range 100-800 ºC with a temperature-increasing rate of 10 ºC/min.
Fourier Transform Infrared Spectroscopy were performed on a
Bruker IFS 66 V/S FTIR spectrometer. The ratio of sample to KBr
was 1/50, scan time was 32s.
4
5.S. Lopez-Orozco, A. Inayat, A. Schwab, T. Selvam and W.
Schwieger, Adv. Mater., 2011, 23, 2602.
6
7
8
.D. P. Serrano, J. M. Escola and P. Pizarro, Chem. Soc. Rev., 2013,
2, 4004.
.W. J. Roth, P. Nachtigall, R. E. Morris and J. ꢀ ejka, Chem. Rev.,
014, 114, 4807.
.J. Cˇ ejka and S. Mintova, Catal. Rev. Sci. Eng., 2007, 49, 457; J.
Qi, T. Zhao, F. Li, G. Sun, X. Xu, C. Miao, H. Wang and X.
Zhang, J. Porous Mater., 2010, 17, 177; S. Bao, G. Liu, X.
Zhang, L. Wang and Z. Mi, Ind. Eng. Chem. Res., 2010, 49,
4
4
. Catalytic Reactions.
2
Two catalytic reactions were used to evaluate catalytic performance
of the G-ZSM-5 materials, and analyses of the catalytic products
were carried out with pulse chromatography (SHIMADZU GC-14C
gas chromatographs equipped with FID detectors ). Samples were
3
972; D. P. Serrano, J. Aguado, G. Morales, J. M. Rodriguez, A.
Peral, M. Thommes, J. D. Epping and B. F. Chmelka, Chem.
Mater., 2009, 21, 641.
4 3
treated with 2 M NH NO for 3h, filtered and dried for 8 h under 80
ºC, then calcined at 550 ºC for 5 h to burn off residual organic
templates and protonated for several times. Catalytic cracking
reactions of 1, 3, 5- triisopropylbenzene were used to evaluate
catalytic performance of the hierarchical ZSM-5 materials.
Comparing with precursor ZSM-5, we found the product treated with
gel-casting method (G-ZSM-5) performed better catalytic activity.
Catalytic cracking of n-hexadecane was used to evaluate catalytic
performance of the hierarchical ZSM-5 materials, comparing with P-
ZSM-5, traditional Beta, Al-MCM-41 and SBA-15, and we found
the product treated with gel-casting method (G-ZSM-5) performed
better Catalytic activity. The catalytic measurement was carried out
according to the following conditions: mass of the catalyst was 0.025
g with 20-40 mesh; reaction temperature was under temperature 250
ºC, 280 ºC,320 ºC, and 360 ºC (no thermal cracking); and the ratio of
n-hexadecane to the catalyst was 0.1 μL/0.025 g. Nitrogen was used
as the carrier gas at a flow rate of 48 mL/min, under the atmospheric
pressure of 0.1MPa. The catalytic cracking reactions of 1,3,5-
triisopropylbenzene was carried out according to the following
conditions: mass of the catalyst was 0.05 g with 20-40 mesh;
reaction temperature was under temperature 200℃, 250℃, and 320
9.Y. Zhu, Z. L. Hua, J. Zhou, L. J. Wang, J. J. Zhao, Y. Gong, W.
Wu, M. L. Ruan and J. L. Shi, Chem. -Eur. J., 2011, 17,14618.
1
1
0.K. Egeblad, C. H. Christensen and M. Kustova, Chem. Mater.,
008, 20, 946.
1.J. Pérez-Ramírez, C. H. Christensen, K. Egeblad, C. H.
2
Christensen and J. C. Groen, Chem. Soc. Rev., 2008, 37, 2530.
12.D. P. Serrano, J. M. Escola and P. Pizarro, Chem. Soc. Rev.,
2013, 42, 4004.
1
1
3.S. Mintova, J. P. Gilson and V. V., Nanoscale, 2013, 5, 6693.
4.S. Mitchell, A. B. Pinar, J. Kenvin, P. Crivelli, J. Kärger and J.
P. Ramírez, Nat. Commun., 2015, 6:8633
1
1
5.P. B. Weisz and J. S. Hicks, Chem. Engng. Sci., 1962,.17,265.
6.Roberta Bigliani IDC Energy Insights. 2013, 5.
17.G. Onyestyák, J. Valyon and K. Papp, Mater. Sci. Eng., A 2005,
412, 48.
1
1
2
8.M. Choi, K. Na, J. Kim, Y. Sakamoto, O. Terasaki and R. Ryoo,
Nature, 2009, 461, 246.
9.B. Louis, F. Ocampo, H. S. Yun, J. P. Tessonnier and M. M.
Pereira, Chem. Eng. J., 2010, 161, 397.
0.L. Xu, S. J. Wu, J. Q. Guan, H. S. Wang, Y. Y. Ma, K. Song, H.
Y. Xu, H. J. Xing, C. Xu, Z. Q. Wang and Q. B. Kan, Catal.
Commun. 2008, 9, 1272.
21.M. Rauscher, T. Selvam, W. Schwieger and D. Freude,
Microporous Mesoporous Mater., 2004, 75, 195.
2.M. Ogura, S. Y. Shinomiya, J.Tateno, Y. Nara, M. Nomura and
E. Kikuchi, Appl. Catal., A 2001, 219, 33.
3.H. B. Zhu, Z. C. Liu, D. J. Kong, Y. D. Wang, X. H.Yuan and Z.
K. Xie, J. Colloid Interface Sci., 2009, 331, 432.
4.Q. F. Tan, X. J. Bao, T. C. Song, Y. Fan, G. Shi, B. J. Shen, C.
H. Liu and X. H. Gao, J. Catal., 2007, 251, 69.
℃
(no thermal cracking); and the ratio of 1,3,5-triisopropylbenzene
2
2
2
to the catalyst was 0.4 μL/0.05 g. Nitrogen was used as the carrier
gas at a flow rate of 48mL/min, under the atmospheric pressure of
0
.1MPa.46-47
8
| New J. Chem., 20xx,xx, xx
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Please do not adjust margins
Page 9 of 10
New Journal of Chemistry
NJC
Paper
2
5.B. Louis, C. Tezel, L. Kiwi-Minsker and A. Renken, Catal.
Today.,2001, 69, 365.
View Article Online
DOI: 10.1039/C5NJ03387J
2
2
6.J. ꢀejka and S. Mintova, Catal. Rev., 2007, 49, 457.
7.A. H. Janssen, I. Schmidt, C. J. H. Jacobsen, A. J. Koster and K.
P. de Jong, Microporous Mesoporous Mater., 2003, 65, 59.
8.D. J. Wang, Z. N. Liu, H.Wang, Z. K. Xie and, Y. Tang,
Microporous Mesoporous Mater. ,2010, 132, 428.
2
2
3
3
9.S. Mitchell, N. Michels, J. Perezramirez, Chem. Soc. Rev., 2013,
4
2, 6094
0.J. S. J. Hargreaves, A. L. Munnoch, Catal. Sci. Technol., 2013,
, 1165
3
1.Z. T. Zhang, Y. Han, F. S. Xiao, S. L. Qiu, L. Zhu, R. W. Wang,
Y. Yu, Z. Zhang, B. S. Zou, Y. Q. Wang, H. P. Sun, D. Y. Zhao
and Y. Wei, J. Am. Chem. Soc., 2001, 21, 5015.
3
3
3
3
3
3
3
3
4
2.C. Young, O. O. Omatete, M. A. Janney and P. A. Menchhofer,
J. Am. Ceram. Soc., 1991, 74, 612.
3.H. T. Wang, X. Q. Liu, H. Zheng, W. J. Zheng and G. Y. Meng,
Ceram. Int., 1999, 25, 177.
4. H. T. Wang, L. M. Huang, Z. B. Wang, A. Mitra and Y. S. Yan,
Chem. Commun., 2001, 1364.
5.Y. J. Jiang, K. Zhang, T. S.Zhao , X. J. Yong, C. T. Luo,
Chemical Reaction Engineering and Technology, 2014, 06, 0528.
6.J. M. Chen, P. Tan, J. Y. Wang, Powder Metallurgy Industry,
2
011, 2, 21.
7.Z. T. Zhang, X. H. Gao, D. O. Xu, L. J. Yan, R. W. Wang, Z. Y.
Zhou, CN. Patent CN201110070493. 2. 2011
8.L. M. Huang, Z. B. Wang, J. Y. Sun, L. Miao, Q. Z. Li, Y. Yan
and D. Y. Zhao, J. Am. Chem. Soc., 2000, 122, 3530.
9.H. T. Wang, Z. B. Wang and Y. Yan, Chem. Commun., 2000, 23,
2
333.
0.H. B. Zou, R. W. Wang, X. X. Li, X. Wang, S. J. Zeng, S. Ding,
L. Li, Z. T. Zhang and S. L. Qiu, J. Mater. Chem. A, 2014, 2,
1
2403
4
4
1.T. Xiao, L. An and H. Wang, Appl. Catal., A, 1995, 130, 187.
2.J. J. Zheng, X. W. Zhang, Y. Zhang, J. H. Ma and R. F. Li,
Microporous Mesoporous Mater., 2009, 122, 264.
4
4
4
4
4
3.S. Abelló, A. Bonilla and J. Pérez-Ramírez, Appl. Catal., A
2
009, 364,191.
4.H. T. Wang, L. M. Huang, Z. B. Wang, A. Mitra and Y. S. Yan,
Chem. Commun., 2001,15, 1364.
5.Z. T. Zhang, Y. Han, L. Zhu, R. W. Wang, Y. Yu, S. L. Qiu, D. Y.
Zhao, and F. S. Xiao, Angew. Chem. Int. Ed. 2001, 40, 7.
6.J. Qi, T. B. Zhao, X. Xu, F. Y. Li, G. D. Sun，Physicochemical
Properties and Catalytic Technology,2010, 12, 17-22.
7.J. H. Li, D. Zhang, X. Li, Chinese journal of inorganic
chemistry, 2004. 29, 2049.
This journal is © The Royal Society of Chemistry 20xx
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3
D hierarchical porous ZSM-5 zeolite as a catalytic material for the cracking of
n-hexadecane is reported.