Synthesis of ZSM-5 with hierarchical porosity: In-situ conversion of the mesoporous silica-alumina species to hierarchical zeolite

Accepted Manuscript Synthesis of ZSM-5 with hierarchical porosity: In-situ conversion of the mesoporous silica-alumina species to hierarchical zeolite Teng Xue, Huaping Liu, Ying Zhang, Haihong Wu, Peng Wu, Mingyuan He PII:

S1387-1811(17)30021-5

DOI:

10.1016/j.micromeso.2017.01.021

Reference:

MICMAT 8090

To appear in:

Microporous and Mesoporous Materials

Received Date: 12 September 2016 Revised Date:

16 November 2016

Accepted Date: 13 January 2017

Please cite this article as: T. Xue, H. Liu, Y. Zhang, H. Wu, P. Wu, M. He, Synthesis of ZSM-5 with hierarchical porosity: In-situ conversion of the mesoporous silica-alumina species to hierarchical zeolite, Microporous and Mesoporous Materials (2017), doi: 10.1016/j.micromeso.2017.01.021. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT Graphical abstract: Hierarchical ZSM-5 with large external surface area, secondary pore volume and regular mesopore size distribution was fabricated through the in-situ conversion of the order mesoporous silica-alumina species, exhibiting the excellent performance when LDPE catalytic cracking was used as the probe reaction. 0.30

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0.15

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10 100 Pore Diameter (nm)

100 50 0 0.0

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LDPE Cracking

o 80 T50(Blank) = 468 Co T50(Con-Z5) = 409 C T50(Meso-Z5) = 359 oC 60

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ACCEPTED MANUSCRIPT Synthesis of ZSM-5 with hierarchical porosity: in-situ conversion of the mesoporous silica-alumina species to hierarchical zeolite

Teng Xue1, Huaping Liu1, Ying Zhang1,2, Haihong Wu1*, Peng Wu1, Mingyuan He1 Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of

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Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China

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Shanghai University of Medicine & Health Sciences, Shanghai 200237, China

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ACCEPTED MANUSCRIPT Abstract Hierarchical ZSM-5 aggregates were fabricated using the conventional surfactant cetyltrimethylammonium bromide (CTABr) as the mesoporogen together with 1, 6-diaminohexane (HDA) as structure-directing agent.

The competition of the

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templates and the subsequent phase separation were effectively avoided. A possible formation mechanism was proposed based on the investigation of the crystallization process. The obtained hierarchical ZSM-5 aggregates were highly crystallized, possessing large external surface area, mesopore volume and regular mesopore size

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distributions. And they were proved to be more efficient in catalytic LDPE cracking due to improved accessibility of large polymer molecules to the active sites. This

using various silica sources.

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method was facile and cost-effective, applicable within a wide SiO2/Al2O3 ratio by

Key word: ZSM-5, hierarchical porosity, dual template, in-situ conversion, LDPE

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cracking

ACCEPTED MANUSCRIPT Introduction Zeolites with regular micropores (usually smaller than 1 nm) are widely used in petroleum and petrochemical industry for its high thermal/hydrothermal stability, strong acidity, well-defined microporosity and shape selectivity.1-3 The sole presence

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of micropores, however, usually imposed diffusion limitation, leading to the low utilization of active sites and poor catalytic activity. Hierarchical zeolites, with at least two levels of pore sizes, were found to be effective in reducing the diffusion limitation and improving the catalytic performance. Preparation of zeolites with hierarchical

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porosity has attracted increasing attention in the recent years. Various novel synthesis strategies have been developed and were summarized in many excellent reviews.4-6 As

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one of the most commonly studied and used zeolites, ZSM-5 is widely used in processes such as cracking, alkylation, acylation, isomerization, aromatization, and aldol condensation. Inevitably, the conventional microporous ZSM-5 suffered from the diffusion limitation during its industrial applications and synthesis of hierarchical ZSM-5 has been the subject of a number of works.7-12 Tremendous progress has been

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made by using a series of dual-functional templates such as gemini-type diquaternary templates with hexamethylene linkers by Ryoo and co-workers12 and amphiphilic surfactant with aromatic groups in the hydrophobic segments by Che and

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co-workers.13 However, most of the dual-functional templates are not commercially available, making the preparation processes tedious and expensive. Synthesis of hierarchical zeolite ZSM-5 in a facile and cost-effective way is still of great academic

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and practical importance. Cationic surfactant cetyltrimethylammonium bromide (CTABr) has been

successfully used in the preparation of MCM series ordered mesoporous materials. And since then, much attention has been paid to the preparation of hierarchical zeolites using CTABr as mesoporogen due to its low cost and commercial availability. However, when CTABr was added to the zeolite synthesis batches, it usually worked in a competitive way with the templating system of micropores, coming out with the formation of physical mixtures of amorphous mesoporous material and bulky zeolite.14, 15 To avoid the phase separation, interaction of the templates should be

ACCEPTED MANUSCRIPT strengthened while the competition should be alleviated. By using the pre-synthesized subnanocrystal-type zeolite seeds with a high degree of polymerization, hierarchical mesoporous ZSM-5 was prepared using CTABr as the soft template. The competition of CTABr with the structure-directing agent (SDA) was lessened by the pre-synthesis

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of the subnanocrystal-type zeolite seeds.16 It is believed, in the opposite scenario, that the competition of the CTABr and the zeolite-forming SDA could also be reduced if the zeolite-forming SDA works after the formation of the mesoporous structure. Thus the CTABr occluded in the mesoporous structure might work as the mesopore genesis

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or the capping agent to further inhibit the further growth of the zeolite crystals, facilitate the formation of zeolite with intercrystalline hierarchical porosity.17-19 This

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has been partially approved in a dry-gel conversion system where pre-synthesized MCM-41 was impregnated with structure-directing agent and then converted through the steam synthesis to mesoporous zeolite ZSM-5. The wrapped CTABr micelle introduced from as-prepared MCM-41 worked as the mesopore genesis of zeolites.20 However, the methods mentioned above were tedious for multiple procedures. It is

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much facile and convenient and of great industrial importance if the whole process be accomplished in one pot through the conventional hydrothermal synthesis. Usually, ZSM-5 is prepared using tetrapropyl ammonium (TPA+) as SDA. Other

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SDAs such as tetraalkyl ammonium other than tetrapropyl ammonium, amines and diamines have been attempted and found to be helpful in the crystallization of ZSM-5.21 Compared with TPAOH, the other SDAs are not so effective and

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specialized, and prolonged crystallization time was usually needed.22 Furthermore, the morphologies and the textural properties of the samples differed based the used SDAs. In our previous study, ZSM-5 aggregates with interparticle mesoporosity formed with nanosized primary particles could be obtained when 1, 6-diaminohexane (HDA) was used.23 However, the mesoporous properties of the obtained zeolite aggregates were not so distinct due to the fusion of the primary nanosized particles. To obtain zeolite aggregates with extinguished intercystalline mesoporous properties, the fusion of the primary nanosized particles should be reduced. In this study, HDA was used as SDA and CTABr as the mesoporogen for the

ACCEPTED MANUSCRIPT synthesis of hierarchically porous ZSM-5. The structure-directing ability of HDA towards ZSM-5 is relatively weak. This makes it work after the formation of the mesoporous silica-alumina species formed with the assistance of CTABr at the initial stage, which effectively avoided the competition of the templates and the subsequent

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phase separation. The mesoporous silica-alumina species were then transformed in-situ to the hierarchical ZSM-5 aggregates with the assistance of HDA while the encapsulated CTABr inhibited the further growth and fusion of primary nanoparticles, constructing extinguished interparticle mesoporosity. The influence of the amount of

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the CTABr, SiO2/Al2O3 ratio and the silica sources on the morphologies, textural and chemical properties of the obtained samples was investigated and a possible formation

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mechanism was brought forward by tracking the crystallization process. The obtained ZSM-5 samples were highly crystallized, possessing large external surface area, mesopore volume and narrow distributed secondary pores. Finally, catalytic cracking of LDPE was used as a probe reaction to investigate the catalytic performance of the obtained hierarchically porous ZSM-5 zeolites. The catalytic performance was greatly

Experimental

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improved due to the improved accessibility of the active sites.

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Synthesis of the mesoporous ZSM-5

The typical synthesis of highly mesoporous ZSM-5 was as follows. 0.86 g of NaOH (Sinopharm Chemical Reagent Co. Ltd) and 0.32 g of NaAlO2 (STREM, 53.6%

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of Al2O3, 43.8% of Na2O) were dissolved in 108 g of hot H2O. And then, 3.644 g of CTABr and 1.63 g of HDA was added and dissolved. After that, 6.06 g of fumed silica (99%, Evonik Industries) as silica source was added and a mixture with the molar composition of SiO2: 0.0167Al2O3: 0.13Na2O: 0.14HDA: 0.1CTABr: 60H2O was obtained. After being stirred for 6 h, the mixture was then transferred into a Teflon-lined stainless steel autoclave and heated statically under autogenous pressure for a certain period of time at 150 oC. The product was recovered by filtration and washing, dried in air, and calcined at 550 oC for 6 h to remove the templates. The calcined product was ion exchanged in aqueous 1.5 mol/L NH4NO3 solution at 80 oC

ACCEPTED MANUSCRIPT and then dried and calcined at 550 oC for 6 h to get the acidic H-form. Thus obtained mesoporous ZSM-5 sample was named after MZ5-FS-0.1-60 (FS stands for fumed silica, 0.1 for the CTABr/SiO2 ratio and 60 for the batch SiO2/Al2O3 ratio). The batch SiO2/Al2O3 ratios were varied in the range of 40-400 by adjusting the amount of

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NaOH and NaAlO2 in the synthesis gels. The CTABr/SiO2 molar ratio was varied by changing the amount of CTABr. Other silica sources such as NaSiO3·9H2O (Sinopharm), silica solution (Qingdao Haiyang Chemical Co. Ltd) and silica powders (Qingdao Haiyang) were also tried and the obtained sample were denoted as

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MZ5-NaS-x-y, MZ5-SS-x-y and MZ5-SP-x-y, respectively. Characterization

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Small angle (0.5-8 °) and wide angle (5-50 °) powder X-ray diffraction (XRD) patterns of the samples were recorded using a Rigaku X-ray diffractometer, with Ni-filtered Cu Kα radiation (λ = 0.15418 nm) at 30 kV and 30 mA at the angular rate of 1 °/min and 5 °/min, respectively. The relative crystallinities of the products were determined from the peak areas in the 2θ range 22.5 °-25 ° using a commercial

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ZSM-5 sample from Nankai University catalyst Co., Ltd as the reference. Scanning electron microscopy (SEM) images were obtained using a field-emission scanning electron microscope (Hitachi S-4800), operated at an

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accelerating voltage of 3 kV. Transmission electron microscopies (TEM) were performed on a FEI Tecnai G2 F30 transmission electron microscope operating at 300 kV.

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N2 adsorption-desorption measurements were performed at -196 oC using a

BELsorp-MAX volumetric adsorption analyzer. The samples were out-gassed at 300 °C for 6 h before the adsorption measurements. The specific surface areas were determined by the Brunauer-Emmett-Teller (BET) method, using data in the p/p0 range 0.01-0.2. The t-plot method was used to discriminate between micro- and meso-porosity. Fourier-transform infrared (FT-IR) spectroscopy was performed (Nicolet NEXUS 670 FT-IR spectrometer) in the range 400-4000 cm−1 using KBr disks. Temperature-programmed desorption of ammonia (NH3-TPD) were carried out

ACCEPTED MANUSCRIPT on a Tianjin XQ TP5080 autoadsorption apparatus. 100 mg of sample was first pretreated at 550 oC for 1 h in a Helium flow and NH3 adsorption was carried out at 150 oC and then, it was pushed with a pure Helium flow at 150 oC for 2 h to remove physically adsorbed ammonia. Finally, it was heated to 550 oC in the Helium flow at a

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Si,

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Al,

13

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rate of 10 oC/min, and the desorbed ammonia was monitored with a TCD. C solid-state MAS NMR spectra were recorded on a VARIAN

VNMRS-400WB spectrometer under one pulse condition.

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Si NMR spectra were

acquired with a 7.5 mm T3HX probe at 79.43 MHz and a spinning rate of 3 kHz. The Al spectra were recorded at a frequency of 104.18 MHz, a spinning rate of 10.0 kHz,

and a recycling delay of 4 s.

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C NMR spectra were recorded with a 7.5 mm T3HX

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probe at 100.54 MHz and a spinning rate of 5 kHz. Catalytic tests

LDPE cracking catalyzed by the obtained acidic H-form ZSM-5 was carried out in a Netzsch STA 449 F3 Jupiter TG-DSC apparatus. LDPE was purchased from Alfa Aesar with shape of powder (≤ 500 µm), density of 0.92 g cm-3 and melting point of

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115 oC determined using differential scanning calorimetry (DSC). 20 mg of grounded polymer and 2 mg of zeolite were carefully weighed, intimately mixed and the mixture was loaded in the 30 µL α-Al2O3 crucibles of the thermobalance. The catalytic pyrolysis was carried out in N2 atmosphere (70 cm3/g) from 25 to 600 oC

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with a ramp rate of 10 oC/min.

Results and discussion The addition of CTABr to the synthesis mixtures did not affect the crystalline

phase of the samples. When a mixture with the molar composition of SiO2: 0.0167Al2O3: 0.13Na2O: 0.14HDA: 60H2O using fumed silica was crystallized at 150 o

C for 14 days, the obtained sample of MZ5-FS-0-60 exhibited well-resolved peaks

characteristic for the MFI structure, without the presence of peaks of other crystalline phases or amorphous phase (Fig. 1a). This was in accordance with that reported previously where crystalline ZSM-5 was obtained with the molar composition of SiO2: 0.0167Al2O3: 0.10Na2O: 0.14HDA: 24H2O after crystallizing at 175 oC for 5 days.23

ACCEPTED MANUSCRIPT Similar patterns could be observed when different amount of CTABr was added to the synthesis mixture. The samples of MZ5-FS-0.05-60 and MZ5-FS-0.1-60 possessed similar crystallinity with that of MZ5-FS-0-60. However, it should be pointed out that when the amount of the CTABr was increased to CTABr/SiO2 ratio of 0.2, the

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obtained solid was poorly crystallized with the relative crystallinity of 54% even after prolonging the crystallization time up to 30 days (Fig. 1d). This showed that too much CTABr with hydrophobic carbon chains might hinder the nucleation as well as the

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growth of the zeolite.

Intensity (a.u.)

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Fig. 1 XRD patterns of MZ5-FS-0-60 (a), MZ5-FS-0.05-60 (b), MZ5-FS-0.1-60 (c) and MZ5-FS-0.2-60 (d).

Textural properties of the obtained samples prepared using different of CTABr

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were characterized using the N2 adsorption-desorption techniques and the isotherms and BJH pore size distributions were presented in Fig. 2. MZ5-FS-0-60 exhibited

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typical type I (a) isotherm according to the IUPAC classification, which is the characteristics of microporous materials having mainly narrow micropores.24 When CTABr was added to the synthesis mixtures, the obtained samples exhibited isotherms with combined characteristics of type I and type II, with obvious steep uptake in the higher relative pressure range (Fig. 2A). This might be ascribed to the capillary condensation in the interpaticle voids. Correspondingly, for samples synthesized with CTABr, regular secondary pores ranged from several nanometers to 100 nm could be observed whereas no pore size distribution could be observed for sample prepared without CTABr (Fig 2B). MZ5-FS-0.05-60 and MZ5-FS-0.1-60 possessed similar

ACCEPTED MANUSCRIPT micropore volume (Vmic, 0.14-0.15 cm3/g) and micropre surface area (Smic, 314-342 m2/g) with that of MZ5-FS-0-60 (0.15 cm3/g and 338 m2/g, respectively). While Vmic (0.09 cm3/g) and Smic (183 m2/g) of MZ5-FS-0.2-60 were relatively smaller. This correlated well with the XRD results where the crystallinity of MZ5-FS-0.2-60 was

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relatively smaller. Largely improved mesoporous properties could be observed for the samples prepared with CTABr added to the synthesis mixtures. The external surface area (Sext) and the secondary pore volume (Vsec) of the samples prepared herein with different CTABr/SiO2 ratios were within the range of 88-126 m2/g and 0.27-0.46

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cm3/g, respectively. This was much larger than the Sext (25 m2/g) and Vsec (0.03 cm3/g) of MZ5-FS-0-60. Correspondingly, Sext/SBET and Vsec/Vt of MZ5-FS-0.05-60,

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MZ5-FS-0.1-60 and MZ5-FS-0.2-60 were much larger than that of MZ5-FS-0-60. Shi and co-workers reported the synthesis of hierarchical mesoporous ZSM-5 zeolites through the self-assembly with subnanocrystal-type zeolite seeds in the presence of a certain amount of ethanol. The prepared samples exhibited mesopores of about 2-3 nm co-existing with micropores. However, Vmic of the samples, which was in

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accordance with the crystallinity, was relatively small. Furthermore, ethanol was unavoidable, increasing the cost of the procedures.16 Zhu and co-workers reported the synthesis of mesoporous zeolite ZSM-5 through the transformation of the

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CTABr-containing MCM-41 in a dry-gel system. But the procedures were tedious due to the preparation of the MCM-41 and then the transformation of the MCM-41 to the mesoporous zeolite. Furthermore the obtained samples were not well crystallized as

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the micropore volumes were much smaller than reported elsewhere.20 Compared to the previous reports, the method reported herein was much simple and practical while the prepared samples were highly crystallized with more extinguished mesoporous properties.

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Pore diameter (nm)

Fig. 2 N2 adsorption-desorption isotherms and BJH pores size distributions of

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MZ5-FS-0-60 (a), MZ5-FS-0.05-60 (b), MZ5-FS-0.1-60 (c) and MZ5-FS-0.2-60 (d).

(b), 0.10 (c) and 0.20 (d). Sample

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Table 1 properties of the samples synthesized with the CTABr/SiO2 ratio of 0 (a), 0.05

BET surface area calculated using BET method applied to the N2 isotherm.

b

Sext,

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Smic, and Vmic, external surface area, micropore area, and micropore volume, respectively, calculated using t-plot method applied to the N2 isotherm. volume calculated from the N2 volume adsorbed at p/p0 = 0.99.

d

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Secondary pore

volume, Vsec=Vt -Vmic.

SEM (Fig. 3a-d) was used to investigate the morphologies of the obtained samples and the location of the secondary pores was observed using SEM and TEM (Fig. 3e-j). The samples prepared with or without CTABr were microspheres aggregated from primary nano-particles, which were similar to those reported by

ACCEPTED MANUSCRIPT Wang and co-workers when HDA was used as structure-directing agent.

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suggested that the use of HDA as structure-directing agent facilitated the formation of ZSM-5 microsphere aggregates. Differences could be observed when CTABr was added. The Sizes of the obtained microsphere aggregates increased with the addition

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of CTABr. Furthermore, with the increase of the amount of CTABr, the size of the microsphere aggregates increased. The size of MZ5-FS-0-60 was ~5 µm. It increased to about 6 µm when CTABr was added to the synthesis mixture with the CTABr/SiO2 molar ratio of 0.05. By increasing the CTABr/SiO2 ratio to 0.1 and 0.2, the size of the

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obtained ZSM-5 microsphere aggregates further increased to ~ 9 µm and ~11 µm, respectively. The obtained ZSM-5 microsphere aggregates were composed of

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nanosized primary particles, no matter CTABr was used or not (inset of Fig. 3a-d). However, the primary particles of MZ5-FS-0-60 were closely stacked and fused with each other, while those of MZ5-FS-0.05-60, MZ5-FS-0.1-60 and MZ5-FS-0.2-60 were stacked loosely, forming the interparticle porosity. This might be a reasonable explanation of the different sizes of the microsphere aggregates.

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Inner morphologies of MZ5-FS-0-60 and MZ5-FS-0.1-60 were investigated by observing the crushed samples and the SEM images were shown in Fig. 3e and Fig. 3f. From Fig. 3e for MZ5-FS-0-60, relatively smooth and solid section could be observed.

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This was quite different from the surface. But for MZ5-FS-0.1-60, the inner part of the microsphere aggregates was also composed of primary nanoparticles, forming abundant interparticle porosity. This reasonably explained why the sample prepared

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with different amount of CTABr exhibited more extinguished mesoporous properties than the sample prepared without CTABr, as indicated in the N2 adsorption-desorption characterization. This was further confirmed by the TEM images in Fig. 3g-Fig. 3j. The TEM images at low magnification for MZ5-FS-0-60 (Fig. 3g) and MZ5-FS-0.1-60 (Fig. 3i) showed that these two samples are both of spherical morphologies with different crystal sizes. Furthermore, differences could also be observed at the edges of the microspheres. The spherical particles of MZ5-FS-0.1-60 were larger with rough edge. The high-resolution TEM image taken at the edge of MZ5-FS-0-60 showed no clear edges of the primary particles; demonstrating that the

ACCEPTED MANUSCRIPT primary nanosized particles were closed aggregated and fused with each other (Fig. 3h). While from the high-resolution TEM image taken at the edge of MZ5-FS-0.1-60 (Fig. 3j), we can found the loosely aggregated nano-partilcles and the interparticle

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mesoporosity formed by the nano-particle aggregation.

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Fig. 3 SEM (a-f) and TEM (g-j) images of MZ5-FS-0-60 (a, e, g and h),

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MZ5-FS-0.05-60 (b), MZ5-FS-0.1-60 (c, f, i and j) and MZ5-FS-0.2-60 (d).

The addition of an appropriate amount of CTABr to the synthesis mixtures did

not significantly influence the acid properties of the obtained ZSM-5 samples. NH3-TPD curves of the acidic H-form samples in Fig. 4 showed that all the samples prepared herein exhibited similar NH3-TPD curves with two well resolved desorption peaks: the low-temperature peak at ca. 200 oC and the high-temperature peak at ~420 o

C, which were ascribed to the weak and strong acid sites respectively. This was in

accordance with the previous reports.25 The NH3-TPD curves of MZ5-FS-0.05-60 and MZ5-FS-0.1-60 were similar with MZ5-FS-0-60, demonstrating that an appropriate

ACCEPTED MANUSCRIPT amount of CTABr had little influence on the acid properties of the obtained samples. However, it should be pointed out that sample MZ5-FS-0.2-60 exhibited much smaller high-temperature NH3-desorption peak than the others, corresponding to the much lower amount of the strong acid. This might be ascribed to the low crystallinity

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of the obtained samples when too much CTABr (CTABr/SiO2 =0.2) was used.

200

2

100

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0 2x106 Time (s)

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and MZ5-FS-0.2-60 (d). B

Intensity (a.u.)

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b

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A

e d c b

a

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1200

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o

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Fig. 4 NH3-TPD curves of MZ5-FS-0-60 (a), MZ5-FS-0.05-60 (b), MZ5-FS-0.1-60 (c)

Fig. 5 Small (A) and Wide-angle (B) XRD patterns and FI-IR spectra (C) of the samples crystallized at 150 oC for 7 days (a), 9 days (b), 11 days (c), 13 days (d), 14 days (e) and 16 days (f).

To investigate the formation mechanism of the hierarchically porous ZSM-5 microsphere aggregates when CTABr was added to the synthesis mixtures, the changes of the obtained solids crystallized for different periods with the molar composition of SiO2: 0.0167Al2O3: 0.13Na2O: 0.14HDA: 0.1CTABr: 60H2O were

ACCEPTED MANUSCRIPT tracked using XRD (small- and wide-angle), FT-IR, N2 adsorption-desorption, SEM and solid-state NMR. No characteristic peaks of MFI phase could be observed in the 2θ range of 5 o -35 o

after crystallizing at 150 oC for 7 days, demonstrating its amorphous nature, as

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displayed in Fig. 5B(a). This was further approved by the FT-IR spectrum where no absorption band at 550 cm-1 ascribing to the zeolite five membered double-ring blocks vibrations could be observed (Fig. 5C(a)). In the small-angle XRD region, a single well-defined peak centered at 1.82

o

could be observed (Fig. 5A(a)). This was much

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same to that of the disordered mesoporous materials such as MSU silicates and also be found for the sample treated for 6 h in the dry-gel conversion of as-synthesized 26 20

It is postulated that CTABr worked firstly

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MCM-41 to mesoporous MFI zeolite.

and facilitated the formation of the mesoporous materials. With the prolonging of the crystallization time, small-angle XRD peaks weakened gradually and almost disappeared after crystallizing for 13 days (Fig. 5A(d)). Simultaneously, Bragg reflections sprouted in the wide-angle XRD region along with an amorphous halo at 9

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days and they became clear and well-resolved at 11 days (Fig. 5B(b) and Fig. 5B(c)). The intensity of diffraction peaks corresponding to the MFI topology increased and thus the relative crystallinity of the obtained samples improved with the increase of the crystallization time (Table 2). Well crystallized zeolite ZSM-5 could be obtained

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after crystallzing at 150 oC for about 13 days, with the almost disappearance of the small-angle diffraction peaks. The absorption band at 550 cm-1 in the IR spectra were

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ascribed to the zeolite five membered double-ring blocks vibrations of the pentasil zeolites and the intensity ratio of the 550 cm-1 and 450 cm-1 band (I550/I450) has been used to assess the formation of MFI zeolite and named IR crystallinity.

27

No

absorption band at 550 cm-1 could be observed for the solid products crystallized for 7 or 9 days. The absorption at 550 cm-1 appeared for the obtained solids crystallized for 11 days and strengthened with the crystallization time. This correlated well with the wide-angle XRD. The evolution of both meso- and micro-structure suggested that the formation of the hierarchically porous ZSM-5 went through the formation of mesoporous aluminosilicate, the corrosion of the mesoporous aluminosilicate with

ACCEPTED MANUSCRIPT HDA and simultaniously the formation of the hierarchically porous ZSM-5 aggregates.

400 300

dV (log d)

Va (cm3/g)

500

A

200 100 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0

3.4 nm

4.5 nm

B

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a b c d e f

600

~12 nm ~17 nm 10

100

Pore diameter (nm)

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p/p0

Fig. 6 N2 adsorption-desorption isotherms and BJH pores size distributions of the

days (e) and 16 days (f).

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samples crystallized at 150 oC for 7 days (a), 9 days (b), 11 days (c), 13 days (d), 14

Table 2 Properties of the samples crystallized at 150 oC for different periods t (d)

r. c. (%)

7

0

b

9

26.8

c

11

66.1

d

13

e

14

a

16

Sextb

Vtc

Vmicb

Vmesod

(m2/g)

(m2/g)

(m2/g)

(cm3/g)

(cm3/g)

(cm3/g)

0

705

63

642

0.92

0.03

0.89

0

609

107

502

0.82

0.06

0.76

0.58

521

232

289

0.59

0.11

0.48

89.6

0. 69

429

305

124

0.45

0.14

0.31

94.6

0.72

426

314

112

0.46

0.14

0.32

0.78

410

315

95

0.43

0.15

0.28

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f

Smicb

EP

a

SBETa

I540/I440

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Sample

103.2

BET surface area calculated using BET method applied to the N2 isotherm.

b

Sext,

Smic, and Vmic, external surface area, micropore area, and micropore volume, respectively, calculated using t-plot method applied to the N2 isotherm. volume calculated from the N2 volume adsorbed at p/p0 = 0.99.

d

c

Total pore

Secondary pore

volume, Vsec=Vt -Vmic.

The N2 adsorption-desorption isotherms, BJH pore size distributions and the

ACCEPTED MANUSCRIPT texture properties of the solids obtained with different crystallization time were presented in Fig .6 and Table 2, respectively. Samples crystallized for 7 or 9 days exhibited type IV isotherms with in the relative pressure range of 0.35-0.55, which is characteristic of capillary condensation in mesoporous channels (~ 3.4 nm). The steep

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uptake became gradual and shifted towards higher pressures with the crystallization time. Furthermore, the amount of the adsorbed N2 lowered. This indicated the increase of pore size of the resulting materials and the breakage of the original mesostructure. As a consequence, the BET surface area and total pore volume of

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mesoporous zeolite decreased while the micropore volume and micropore surface area increased. The micropore volume and micropore surface area reached the ultimate of

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0.14 cm3/g and 310 m2/g respectively at about 13 days, demonstrating the complete conversion of the mesostructure to the crystalline ZSM-5. The mesoporosity partially reserved with the external surface area of ~110 m2/g and mesopore volume of ~0.3

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cm3/g.

Fig. 7 SEM images of the samples crystallized at 150 oC for 7 days (a), 9 days (b), 11 days (c), 13 days (d), 14 days (e) and 16 days (f).

The revolution of the morphologies was exhibited in Fig. 7. The solids obtained after crystalizing for 7 days exhibited nano-particle morphology, similar to that for the disordered Al-MCM-41 in the previous reports (Fig. 7a) 28, 29. This was in accordance

ACCEPTED MANUSCRIPT with the XRD and N2 adsorption-desorption characterization. Trace amount of small microspheres with the size of about 8 µm appeared after 9 days and the spheres were aggregated with the primary nano-crystals. Bragg reflections could be observed in the wide-angle XRD region at this period and thus the microspheres might be ascribed to

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the initially formed crystalline ZSM-5. The microspheres increased while the amount of the amorphous phases decreased with crystallization time, corresponding to the increased crystallinity (Fig. 7b-7f). The products were dominated by microspheres consisted of clear primary nanoparticles while nearly no obvious amorphous phases

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could be observed after crystallizing for 13 days. Further prolonging the crystallization time had little effect on the morphology of the obtained samples. It

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should be pointed that the initial size of the microspheres was about 8 µm at 9 days (Fig.7b) but increased suddenly to about 12 µm at 11 days with amorphous phase attached to the surface (Fig 7c and inset of Fig 7c). The amorphous phase attached on the surface disappeared after prolonging the crystallization time to 13 days accompanied with slight increase of the particle size and the appearance of the

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primary nanocrystals on the surface. This suggested that the growth of the aggregated microspheres might proceed through the formation of the smaller crystalline aggregates formed with the extremely small primary particles at the initial stage, the

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attachment of the amorphous phases on the small aggregates and then the transformation of the attached amorphous phases to the nanocrystalline ZSM-5 primary particles, as found in the crystallization SSZ-13.30 Thus the aggregated

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microspheres grew up layer-by-layer till the depletion of the amorphous species and simultaneously primary nanocrystals grew larger with clear edges through the Ostwald ripping.

ACCEPTED MANUSCRIPT 13

C MAS NMR 30 54

f

45

23

14

e d c

a 80

40 20 Chemical shift(ppm)

0

f

7.2

e

7.3

d

7.3

c

7.8

b

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Al MAS NMR

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27

60

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b

10

a

10.8

100

80

60

40

20

0

-20

Chemical shift (ppm)

29

Si MAS NMR

113

106

116

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f

e

d

c

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b

103

112

93

a

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-80

-100 -120 Chemical shift (ppm)

-140

Fig. 8 13C, 27Al and 29Si MAS NMR spectra of the samples crystallized at 150 oC for 7 days (a), 9 days (b), 11 days (c), 13 days (d), 14 days (e) and 16 days (f).

Fig. 8 exhibited the

13

C,

29

Si,

27

Al MAS NMR spectra of the as-made samples

crystalized for different periods. The role of the CTABr and the HDA played at different crystallization stages was investigated using the 13C MAS NMR spectra. For the all the obtained solids, obvious resonances at 54, 30, 23 and 14 ppm could be observed. These could be ascribed to the chemical shifts of the carbons at different

ACCEPTED MANUSCRIPT 31

positions of the CTABr, as indicated in the previous reports.

The patterns and the

locations of the resonance peaks remained the same throughout the crystallization, demonstrating that the chemical surroundings did not significantly change and CTABr was not expelled out after the formation the zeolite ZSM-5. Additional resonance at

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45 ppm appeared for the samples obtained after crystallizing for more than 11 days, which was due to the α-C of the HDA. The appearance of the resonance at 45 ppm after crystallizing for 11 days correlated well the observation of the Bragg reflections in the wide-angle XRD region, showing that HDA worked after the formation of the

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mesoporous structure and might only participate in the direction of crystalline zeolite ZSM-5. The 27Al MAS NMR spectra of all the obtained solids showed a single signal

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centered at approximately 54 ppm. This was assigned to the four-coordinated Al atoms in aluminosilicate lattices. The linewidths (full-width-at-half maximum, FWHM) became narrower from ~10.8 ppm to ~7.2 ppm with the increase of the crystallization time, indicating the transformation from the amorphous phase to the crystalline zeolite.

32

Furthermore, the FWHM for the well crystallized ZSM-5

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samples was still slightly larger (~7.2 ppm). This might be ascribed to the nanocrystalline properties of the primary particles. The 29Si MAS NMR spectra of the mesoporous solids obtained at 7 days showed resonances centered at -93, -103 and -112 ppm, which were assigned to the Q2, Q3 and Q4 29Si sites, respectively.33 The Q2

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and Q3 bands decreased obviously in intensity with the increase of the crystallization time, suggesting the dehydroxylation occurred within the silica species. Finally,

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resonances at −106 ppm and −113 ppm partly overlapped with a resonance at approximately −116 ppm dominated, in accordance with those reported earlier for nanosized ZSM-5 zeolites with similar SiO2/Al2O3 ratios.34, 35 Mixed templates of surfactant molecules and small organic ions have been

attempted for preparation of zeolites with hierarchical porosity since the discovery of the MCM-series materials. But usually, composite materials of amorphous mesoporous material and bulky zeolite were obtained.36,

37

To avoid the phase

separation during the synthesis, tremendous efforts have been made besides the use of dual-function templates. It was believed that the interaction of the zeolite with

ACCEPTED MANUSCRIPT monofunctional surfactants should be strong enough to compete with the zeolite-forming SDA to allow for successful dual-template synthesis of hierarchical zeolites. Based on this consideration, Hensen’s group used C22H45−N+(CH3)2− (CH2)4−N+(CH3)2−C4H9Br2

(C22−4−4Br2)

and

C16H33−[N+−methylpiperidine]

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( C16MP), which were thought to possess sufficiently strong interaction with the growing zeolite surface to effectively compete with the zeolite SDA, for the synthesis of hierarchical zeolite SSZ-13. Highly mesoporous SSZ-13 zeolites assembled of small nanocrystals were obtained. 38, 39 Cetyltrimethylammonium bromide (CTABr) as

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mesoporogenous additives in zeolite synthesis gel mixtures to prepare mesoporous zeolites in one step usually failed due to its low competitive ability with the

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zeolite-forming SDA (e.g., tetrapropylammonium for MFI zeolite). Thus, the competition with the zeolite-forming SDA should be alleviated to obtain the mesoporous zeolites when CTABr was used as the mesoporogen. From this point of view, hierarchically mesoporous ZSM-5 zeolites were directly fabricated by controlling the zeolite seed formation and using CTAB as a soft template with the aid

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of ethanol. Zeolite seeds in the form of subnanocrystals were prepared and then allowed to interact with the surfactant for mesostructure assembly.16 In the opposite scenario, we postulated that the competition of the CTABr and the zeolite-forming

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SDA (HDA herein) was reduced. The use of HDA with the weak structure-directing ability as the zeolite-forming SDA let the formation of the mesoporous structure go firstly. After the formation of the mesoporous structure, the HDA worked and

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facilitated the formation of the zeolite ZSM-5 aggregates while the encapsulated CTABr during the formation of the mesoporous structure inhibited the further growth and fusion of primary nanoparticles. The interparticle mesoporosity preserved as large as possible.

This method for the preparation of hierarchically porous ZSM-5 could be applied within a wide SiO2/Al2O3 ratio range from the batch SiO2/Al2O3 ratio of 40 to 400 (Fig. S1-S3 and Table S1). However, the mesoporous properties decreased with the increase of batch SiO2/Al2O3 ratio. And when the batch SiO2/Al2O3 ratio was higher than 200, the crystallization time was reduced to 8 days for the well crystallized

ACCEPTED MANUSCRIPT samples. The obtained samples tend to grow larger, forming bulk crystals with different morphologies, which may lead to the decrease of the mesoporous properties. Even so, the Vmeso and Sext for the sample of MZ5-FS-0.1-400 were 0.11 cm3/g and 74 m2/g, respectively. This was still larger than that of MZ5-FS-0-60 and that reported with

lower

SiO2/Al2O3

ratios.

Diamines

have

been

used

as

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elsewhere

structure-directing agent for the preparation zeolite ZSM-5. But usually, the SiO2/Al2O3 ratio range was relatively narrow. And when the SiO2/Al2O3 ratio increased, the amount of the structure-directing agent increased.23, 40 The addition of

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CTABr herein greatly widened the SiO2/Al2O3 ratio range of the synthesis. However, with the increased of the SiO2/Al2O3 ratio, fusion of the primary crystals appeared and

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finally bulk crystals formed, leading to the deteriorated mesoporous properties. The SiO2/Al2O3 ratio of the synthesis mixture influenced the nucleation and growth rates of the crystals and when the SiO2/Al2O3 ratio increased the nucleation and growth rates were enhanced. This might destroy the compromise between the templates and then the templates worked in a competitive way again and forming ZSM-5 zeolite

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crystals with different morphologies (Fig. S2e). Various silica sources such as sodium silicate, silica solution and silica powders could be used herein for the preparation of hierarchically porous ZSM-5, as depicted in Fig. S4-S6 and Table S2. It should be

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mentioned that when silica powders were used, bulk particles and aggregated spheres co-existed in the final products, as indicated in Fig. 2e. The crystallinity of obtained sample was slightly lower even after longer crystallization time. This might be

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ascribed to the mismatch of the dissolution, condensation and decondensation of the solid silica species with the formation of the mesoporous structure, which subsequently influenced the formation of the hierarchically porous ZSM-5 nanocrystal aggregates.41, 42 Acid catalyzed LPDE cracking, which was thought to be a suitable probe reaction for diffusion limited reactions due to the nature of the branched polyethylene chain (diameter of 0.494 nm), was used to evaluate the catalytic performance of the prepared samples.43 Reaction with programmed temperature was used to investigate the relationship of LDPE conversion versus temperature, which was the reflection of

ACCEPTED MANUSCRIPT the accessibility of acid sites on the zeolites. Pure LDPE decomposed at very high temperature with T50 (temperature for 50% conversion) of 468 oC. The addition of ZSM-5 as catalyst greatly reduced the decomposing temperatures (Fig. 9). When MZ5-FS-0-60 was used as the catalyst, the T50 was reduced to 409 oC, with the T50

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reduction of nearly 60 oC. Similar trend can be observed in the previous reports.44 The cracking temperatures were further reduced when the hierarchically porous ZSM-5 aggregates prepared with the addition of CTABr to the synthesis mixtures were used. The T50 of the LDPE catalytic cracking over sample MZ5-FS-0.05-60 and sample

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MZ5-FS-0.1-60 was reduced to 362 oC and 359 oC, with the shift of 106 oC and 109 o

C towards lower temperature compared with the thermal cracking, respectively. This

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was comparable to that reported for the nano-crystallite oriented self-assembled ZSM-5 prepared with the assistance of F− and even the mesoporous beta and ferrierite obtained by the desilication44-46 and correlated well with mesoporous properties of the samples. Although sample MZ5-FS-0.2-60, prepared with the CTABr/SiO2 ratio increased to 0.2, possessed more pronounced mesoporous properties, it did not show

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superior performance to sample MZ5-FS-0.05-60 and sample MZ5-FS-0.1-60. LDPE is a polymer constituted of long branched hydrocarbon chains. Diffusion limitations were reported to play a significant role during the catalytic cracking, which could be

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alleviated by introducing mesoporosity to the zeolite catalysts. The greatly improved catalytic performance of the hierarchically porous ZSM-5 aggregates prepared herein with appropriate amount of CTABr as mesoporogenous template could be attributed

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to the increased external surface area and exposed acid sites as a consequence of the introduction of regular secondary interparticle pores. Furthermore, the acid strength on accessible acid sites played an important role on the induction of the start-up steps of the cracking reaction influencing the cracking performance.44 This might be the possible reason for the deteriorated performance of sample MZ5-FS-0.2-60, compared with that of sample MZ5-FS-0.05-60 and sample MZ5-FS-0.1-60.

ACCEPTED MANUSCRIPT A

80 60

c b d a

blank

40 20 0

200

250

300

350

400

450

500

550

Temperature (oC)

500 B

SC

468

409 400

389

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T50 (oC)

450

362

350

300

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Conversion of LDPE (%)

100

359

king 0-60 1-60 2-60 5-60 Crac Z5-FS- -FS-0.0 5-FS-0. 5-FS-0. l a m 5 Z Z M r Z e M M M Th

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Fig. 9 TG profiles (A) of LDPE thermal cracking and catalytic over MZ5-FS-0-60 (a), MZ5-FS-0.05-60 (b), MZ5-FS-0.1-60 (c) and MZ5-FS-0.2-60 (d) and the

Conclusions

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temperatures for 50% conversion (B) during the cracking over the different samples.

Hierarchical ZSM-5 aggregates were fabricated using CTABr as mesoporogen

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together with 1, 6-diaminohexane as structure-directing agent. During the crystallization, mesoporous silica-alumina species formed firstly at the convenience of CTABr and then transformed in-situ to the hierarchical ZSM-5 aggregates with the assistance of 1, 6-diaminohexane. The weak structure-directing ability of 1, 6-diaminohexane avoided the competition with the mesogenerous template and consequently the phase separation. Furthermore, 1, 6-diaminohexane as the structure-directing agent facilitated the formation of the ZSM-5 aggregates while the encapsulated CTABr inhibited the further growth and fusion of primary nanoparticles, preserving the interparticle mesoporosity as large as possible. The obtained

ACCEPTED MANUSCRIPT hierarchical ZSM-5 aggregates were highly crystallized, with large external surface area, mesopore volume and regular mesopore size distributions. And they exhibited improved catalytic performance in the large-molecule involved reactions due to the

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improved accessibility of the active sites.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (21403070, 21573073), National Key Technology R&D Program (2012BAE05B02)

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and Shanghai Leading Academic Discipline Project (No. B409).

1.

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References A. Corma, Chem Rev, 1997, 97, 2373-2420.

2. M. E. Davis, Nature, 2002, 417, 813-821.

3. V. Van Speybroeck, K. Hemelsoet, L. Joos, M. Waroquier, R. G. Bell and C. R. A. Catlow, Chem Soc Rev, 2015, 44, 7044-7111.

4004-4035.

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4. D. P. Serrano, J. M. Escola and P. Pizarro, Chem. Soc. Rev., 2013, 42,

5. K. Möller and T. Bein, Chem Soc Rev, 2013, 42, 3689.

7234-7261.

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6. Y. Wei, T. E. Parmentier, K. P. de Jong and J. Zecevic, Chem Soc Rev, 2015, 44,

7. D. P. Serrano, J. Aguado, G. Morales, J. M. Rodrí guez, A. Peral, M. Thommes, J.

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D. Epping and B. F. Chmelka, Chem Mater, 2009, 21, 641-654. 8. N. R. Shiju and V. V. Guliants, Appl Catal A: Gen, 2009, 356, 1-17. 9. M. Bejblová, D. Procházková and J. Čejka, ChemSusChem, 2009, 2, 486-499. 10. L. B. Young, S. A. Butter and W. W. Kaeding, J Catal, 1982, 76, 418-432. 11. N. Chu, J. Yang, C. Li, J. Cui, Q. Zhao, X. Yin, J. Lu and J. Wang, Microporous Mesoporous Mater, 2009, 118, 169-175. 12. M. Choi, K. Na, J. Kim, Y. Sakamoto, O. Terasaki and R. Ryoo, Nature, 2009, 461, 246-249. 13. D. Xu, Y. Ma, Z. Jing, L. Han, B. Singh, J. Feng, X. Shen, F. Cao, P. Oleynikov,

ACCEPTED MANUSCRIPT H. Sun, O. Terasaki and S. Che, Nature Commun, 2014, 5, 1-9. 14. A. Karlsson, M. Stöcker and R. Schmidt, Microporous Mesoporous Mater, 1999, 27, 181-192. 15. J. S. Beck, J. C. Vartuli, G. J. Kennedy, C. T. Kresge, W. J. Roth and S. E.

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Schramm, Chem Mater, 1994, 6, 1816-1821. 16. Y. Zhu, Z. Hua, J. Zhou, L. Wang, J. Zhao, Y. Gong, W. Wu, M. Ruan and J. Shi, Chem Eur J, 2011, 17, 14618-14627.

17. S. P. Naik, J. C. Chen and A. S. T. Chiang, Microporous Mesoporous Mater,

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2002, 54, 293-303.

18. S. P. Naik, A. S. T. Chiang, R. W. Thompson, F. C. Huang and H. Kao,

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Microporous Mesoporious Mater, 2003, 60, 213-224.

19. F. Hasan, R. Singh, G. Li, D. Zhao and P. A. Webley, J Colloid Interf Sci, 2012, 382, 1-12.

20. M. B. Yue, L. B. Sun, T. T. Zhuang, X. Dong, Y. Chun and J. H. Zhu, J Mater Chem, 2008, 18, 2044.

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21. B. M. Lok, T. R. Cannan, C. A. Messina, Zeolites, 1983, 3, 282-291. 22. R Singh, P K Dutta, ChemInform, 2004, 35. 23. L. Chen, S. Y. Zhu, Y. M. Wang and M. He, New J Chem, 2010, 34, 2328.

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24. M. Thommes, K. Kaneko, A. V. Neimark, J. P. Olivier, F. Rodriguez-Reinoso, J. Rouquerol and K. S. W. Sing, Pure Appl Chem, 2015, 87. 25. C. S. Triantafillidis, A. G. Vlessidis, L. Nalbandian and N. P. Evmiridis,

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Microporous Mesoporous Mater, 2001, 47, 369-388. 26. S. S. Kim, W. Zhang and T. J. Pinnavaia, Science, 1998, 282, 1302-1305. 27. P. A. Jacobs, E. G. Derouane and J. Weitkamp, J Chem Soc, Chem Commun, 1981, 591-593.

28. M. Adjdir, T. Ali-Dahmane, F. Friedrich, T. Scherer and P. G. Weidler, Appl Clay Sci, 2009, 46, 185-189. 29. H. Chen and Y. Wang, Ceram Int, 2002, 28, 541-547. 30. M. Kumar, H. Luo, Y. Román-Leshkov and J. D. Rimer, J Am Chem Soc, 2015, 137, 13007-13017.

ACCEPTED MANUSCRIPT 31. D. Xu, J. Feng and S. Che, Dalton Trans, 2014, 43, 3612. 32. E. Oldfield, J. Haase, K. D. Schmitt and S. E. Schramm, Zeolites, 1994, 14, 101-109. 33. R. Ravishankar, C. E. A. Kirschhock, P. Knops-Gerrits, E. J. P. Feijen, P. J.

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Grobet, P. Vanoppen, F. C. De Schryver, G. Miehe, H. Fuess, B. J. Schoeman, P. A. Jacobs and J. A. Martens, J Phys Chem B, 1999, 103, 4960-4964.

34. C. J. H. Jacobsen, C. Madsen, T. V. W. Janssens, H. J. Jakobsen and J. Skibsted, Microporous Mesoporous Mater, 2000, 39, 393-401.

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35. T. Xue, L. Chen, Y. M. Wang and M. He, Microporous Mesoporous Mater, 2012, 156, 97-105.

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36. L. Huang, W. Guo, P. Deng, Z. Xue and Q. Li, J Phys Chem B, 2000, 104, 2817-2823.

37. A. Karlsson, M. Stöcker and R. Schmidt, Microporous Mesoporous Mater, 1999, 27, 181-192.

38. X. Zhu, R. Rohling, G. Filonenko, B. Mezari, J. P. Hofmann, S. Asahina and E. J.

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M. Hensen, Chem. Commun., 2014, 50, 14658-14661.

39. L. Wu, V. Degirmenci, P. C. M. M. Magusin, B. M. Szyja and E. J. M. Hensen, Chem Commun, 2012, 48, 9492-9494.

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40. L. L. Korobitsyna, L. M. Velichkina, A. V. Vosmerikov, V. I. Radomskaya, E. S. Astapova, N. V. Ryabova and O. A. Agapyatova, Russ J Inorg Chem, 2008, 53, 169-173.

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41. K. E. Hamilton, E. N. Coker, A. Sacco, A. G. Dixon and R. W. Thompson, Zeolites, 1993, 13, 645-653. 42. E. N. Coker and J. C. Jansen, in Synthesis, Springer Berlin Heidelberg, Berlin, Heidelberg, 1998, pp. 121-155. 43. J. Agullo, N. Kumar, D. Berenguer, D. Kubicka, A. Marcilla, A. Gómez, T. Salmi and D. Y. Murzin, Kinet Catal, 2007, 48, 535-540. 44. H. Zhang, Y. Ma, K. Song, Y. Zhang and Y. Tang, J Catal, 2013, 302, 115-125. 45. J. Pérez-Ramírez, S. Abelló, A. Bonilla and J. C. Groen, Adv Funct Mater, 2009, 19, 164-172.

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46. A. Bonilla, D. Baudouin and J. Pérez-Ramírez, J Catal, 2009, 265, 170-180.

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Highlights

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>Mesoporous ZSM-5 was prepared using 1, 6-diaminohexane (HDA) and CTABr > Competition of HDA and CTABr was effectively avoided > Ordered mesoporous silica-alumina species formed firstly at the convenience of CTABr > It transformed in-situ to the hierarchical ZSM-5 aggregates with assisstance of HDA > This method is facile and cost-effective, applicable in a wide SiO2/Al2O3 ratio range