CHEMICAL ENGINEERING JOURNAL
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2025
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IF 13.2
Zijun Huang,Yubing Li,Yongming Luo,Dingkai Chen,Xiaohua Cao,Hao Wang,Shuquan Huang,Dedong He
The distribution and location of active metal in zeolite determine the performance in catalytic processes, and catalysts encapsulated with small-sized and highly dispersed metal sites have received tremendous progress in propane dehydrogenation (PDH), while the identification of the migration of metal sites in silicalite-1 (S-1) and its structural characteristics have been rarely investigated. In this work, we engineered the location of cobalt in the S-1 by developing dissolution and recrystallization method, and migration behavior of cobalt during recrystallization stage is systematically investigated. It is found that active Co 2+ species are mainly located at the intersection of straight and sinusoidal β channels, and the abundance of Co 2+ located at β channel increase Lewis acid site of the catalyst, which regulates the catalyst more active in the PDH process. This work enriches a deep understanding of the β-located Co 2+ sites, and provides a novel idea for the synthesis of high-performance PDH catalysts.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
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IF 3.8
Shiwei Wang,Tianhao Li,Yanle Li,Hongfeng Yin,Ziqi Tian,Hongbo Yu
Supported Pt nanoparticles (NPs) exhibit excellent activity for the selective oxidation of glycerol (GL) derived from biodiesel production to high-value dihydroxyacetone (DHA). However, their selectivity to DHA is not satisfactory due to the preferential oxidation of the primary −OH in GL. In this study, Pt@Sn-MFI with ∼4.0 nm Pt NPs and different Si/Sn ratios were synthesized by an in situ encapsulation strategy. The optimized Pt@Sn-MFI-80 catalyst presents a 74.8% selectivity to DHA with a GL conversion of 43.5% at 60 °C. Our experiments and density functional theory (DFT) calculations indicated that the excellent selectivity was ascribed to the synergistic effect between Pt and Sn-MFI. Sn-MFI turned Pt NPs into an electronic-poor state so that suppressed further oxidation of glyceraldehyde (GLD); then, Sn-MFI triggered isomerization of GLD to generate DHA. The core–shell structure not only guaranteed an intimate contact between Pt and Sn-MFI but also enhanced the stability of the active Pt NPs.
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RSC Advances
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2025
·Vol. 15
·期 12
·9467-9478
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IF 4.6
Fuchao Li,Jianqiang Liu,Enhui Xing,Xiaoli Wei,Jianhong Gong,Yibin Luo,Xingtian Shu
A series of steam and phosphorus modified ZSM-5 samples were prepared to investigate the effect of pore structure and acid property on ethylene oligomerization. Characterization results showed that steam treatment contributed to generate mesopores with pore sizes of 2–3 nm and 10–20 nm, while progressive aggregation of phosphorus species on the exterior surface resulted in blockage of channels. Dealumination of framework aluminum led to a gradual decline in total acidity and acid strength with an increase of steam temperature or P/Al ratio. Sufficient strong acid sites and enhanced accessibility to the inner active sites were crucial factors in conversion of ethylene to liquid fuels. The steam modified sample at 700 °C (HZ-700) obtained the highest yield of liquid fuels up to 78.1%, which demonstrated an increase of 40% in comparison with the unmodified sample. Due to improved diffusional capacity originating from mesopores, HZ-700 showed a higher deactivation stability than the phosphorus modified sample at similar conversion levels. This work will provide some insight into the development of zeolite-based catalyst for ethylene oligomerization to liquid fuels.
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PubMed
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2025
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IF 3.7
Xinyi Gao,Qiancheng Zheng,Zhengbao Wang
The preparation of dispersible MFI-type zeolite nanoparticles with open micropores is challenging. Herein, a rapid and effective ultrasound-assisted liquid-phase exfoliation method along with a freeze-drying process for redispersion of calcined Silicalite-1 (S-1) zeolite nanoparticle aggregates using 3-aminopropanol as an exfoliating agent is demonstrated. The exfoliation of S-1 zeolite nanoparticles is characterized by X-ray diffraction, scanning electron microscopy and DLS particle size analysis. The effects of drying methods of as-synthesized zeolite nanoparticle suspension, zeolite contents in frozen nanoparticle suspension, exfoliating agent concentrations, and zeolite doses in ultrasonic suspension on exfoliation efficiency are systematically investigated. It is found that the S-1 zeolite nanoparticle (∼70 nm) achieves a yield up to 95 % through a 30 min ultrasonic exfoliation in a 3-aminopropanol solution along with a freeze-drying process. The proposed exfoliation mechanism involves two primary stages: guest molecule insertion followed by water expansion, both substantially enhanced by tip sonication. This work offers a comprehensive understanding of the exfoliation process, provides valuable insights into the dispersion of sintered zeolite nanoparticles.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Guojun Lv,Tao Wang,Xuyang Zou,Jialing Shen,Jiangzhang Wang,Yan Chen,Fumin Wang,Xubin Zhang
Framework doped iron materials such as Fe-MFI zeolite is an important heterogeneous Fenton-like catalyst for tetracycline degradation. Introduction of mesopore can enhance the tetracycline degradation performance for hollow Fe-MFI zeolite, however its positive effect is extremely limited ascribed to the essence of active sites of confined framework iron species. In this work, highly dispersed copper oxide on the hollow Fe-MFI zeolite CuO/FeS-1 was synthesized via an impregnation procedure and applied as heterogeneous catalyst for the tetracycline degradation. The synthesized CuO/FeS-1 was characterized by Scanning electron microscopy, Transmission electron microscopy , X-ray diffraction, UV–vis absorption spectrometry, Fourier transform infrared spectroscopy , Nitrogen adsorption-desorption and X-ray photoelectron spectroscopy. At pH = 7.0, CuO/FeS-1 revealed the highest tetracycline degradation rate of 99.6 % at experimental conditions: [TCE] = 30 mg/L, [PMS] = 1.0 g/L, [Catalyst] = 1.0 g/L, 333 K, and the largest degradation rate constant of 1.26 min −1 , which was 3.4 folds of FeS-1 zeolite and 1.8 folds of CuO . Electron paramagnetic resonance (EPR) technology disclosed that •OH, SO 4 • − , 1 O 2 and •O 2 − species were all the active species for CuO/FeS-1 zeolite in the tetracycline degradation. Furthermore, possible intermediates in the degradation of tetracycline over CuO/FeS-1 zeolite were identified with liquid chromatography-mass spectrometry (LC-MS).
研究领域:
环境科学
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催化化学
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AICHE JOURNAL
·
2021
·Vol. 67
·期 6
·e17184
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IF 3.993
Jiancheng Lan,Linzhe Li,Wensen Song,Hammad Saulat,Haowen Wu,Jianhua Yang,Chengmin Yang,Yang Li,Jinming Lu,Yan Zhang
Pure-silica MFI zeolite membrane composed of intergrown four prism crystals was fabricated by using tetrabutylammonium (TBA + ) and tetraethylammonium (TEA + ) as cooperating templates and the induced function of MFI seeds under synthesis solution with molar composition of 1TEOS:0.2TBAOH:0.2TEABr:180H 2 O. The ethanol/water separation factor was 64 with a flux of 1.40 kg m −2 hr −1 for 5 wt% ethanol/water mixture at 60°C. In contrast, single TBAOH and TEAOH template led to formation of uncontinuous MEL and MFI membrane respectively, without ethanol-selectivity. The behavior of quaternary ammonium (TBA + and TEA + ) varied in different system: (a) In “TBA + + TEA + ” system, TBA + and TEA + were incorporated into MFI zeolite channel simultaneously; (b) In “TPA + + M + ” system (M = TEA or TBA), either TEA + or TBA + could not be occluded into channel, however, appropriate amount of TBA + could accelerate membrane crystallization, meanwhile increase in TEA + slowed down crystallization rate of MFI membrane. This work extends the alternative preparation approaches of ethanol perm-selective MFI membrane.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2023
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IF 5.2
Pingping Li,Lei Han,Donghun Kim,Kemal Celebi
The demand for high aspect ratio zeolite crystals has been increasing dramatically for many applications, ranging from catalysis to membrane separations . However, manufacturing such platelike crystals usually requires energy-intensive and time-consuming synthesis procedures. Here, by employing a thin-wall tubular reactor, we report for the first time a fast synthetic strategy that yields preferentially- b -oriented platelike MFI crystals within minutes of hydrothermal treatment . Various synthesis conditions such as hydrolysis, precursor aging, chemical compositions, etc. can be quickly optimized within days. Such optimization resulted in highly crystalline platelike crystals with lateral dimensions up to ∼5 μm length in c -axis or ultra-thin crystals with ∼25 nm thickness. Meanwhile, non-platelike MFI crystals can even reach 135 μm lateral size in 24 h. This fast synthetic strategy can be further generalized for the preparation and optimization of diverse important materials including MOFs , COFs , and other zeolites, benefiting both fundamental research and practical applications.
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CRYSTAL GROWTH & DESIGN
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2023
·
IF 3.8
Xunming Su,Zhong-Pan Hu,Jingfeng Han,Yingxu Wei,Zhongmin Liu
Developing highly efficient methods to selectively incorporate active metal sites into the zeolite framework is crucial for the large-scale utilization of metal-zeolites in various catalytic reactions including alkane conversion. Herein, ferrous gluconate is developed as an efficient metal precursor to embed Fe atoms into the MFI siliceous zeolite framework. The crystallization time and Si/Fe ratio are systematically investigated. It is revealed that the ferrous gluconate is well soluble and stable under alkaline conditions, allowing ferrous gluconate to participate in the whole crystallization course of zeolite. Multiple characterizations demonstrate that the tetrahedrally coordinated Fe atoms are selectively incorporated into the MFI siliceous zeolite framework (Fe-MFI). A catalytic test in propane dehydrogenation shows that the optimized Fe-MFI zeolite possesses high activity, propylene selectivity, and durability. This study opens an efficient strategy to incorporate isolated Fe atoms into the zeolite framework.
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JOURNAL OF MEMBRANE SCIENCE
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2025
·
IF 9
Pingping Li,Ming Zhang,Yubin Hu,Lei Han,Gang Lou,Pengyuan Wu,Oleksiy Penkov,Junjie Zhao,Kemal Celebi
Mixed matrix membranes (MMMs) with aligned microporous sheets offer enhanced molecular transport. Platelike MFI zeolite crystals can form such MMMs with aligned micropores. However, platelike MFI synthesis suffers from twinning and crystal junctions. Here, we present a method to minimize and preferentially detach these twins and junctions to obtain standalone platelike MFI crystals with high aspect ratios (ca. 4.3 μm by 120 nm). These platelike crystals can be synthesized in kilogram scale and do not aggregate after calcination, exhibiting ∼100 % dispersion yield, in contrast to the ultrathin nanosheets, which lose ∼90 % to aggregation. Twins and crystal junctions are eliminated using a preferential detaching strategy by selectively etching the twin boundaries and junctions. Discrete crystals are aligned in a 2.8 μm thick Pebax matrix to prepare highly b -oriented MFI MMMs with 30 % MFI loading, exhibiting CO 2 permeances up to 37 GPU, and CO 2 /N 2 separation factors up to 16.8 at ambient pressure.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2024
·
IF 4.8
Guojun Lv,Hao Ruan,Xuyang Zou,Yan Chen,Xubin Zhang,Fumin Wang
Solvent-free synthesis method in zeolite preparation can largely decrease the generation of wastewater and improve the zeolite yield by simply grinding and hydrothermal treatment for the solid raw materials, and accordingly is considered as one of the most promisingly green and sustainable synthesis strategy for the metal-doped zeolite materials. However, there are scarcely any reports on the solvent-free synthesis and catalytic application of tungsten-doped zeolite materials. In this work, tungsten-doped MFI zeolites were prepared with solvent-free synthesis method and used as heterogeneous catalyst for cyclohexene epoxidation reaction. The synthesized tungsten-doped MFI zeolites displayed a monoclinic (P21/n) space group attributed to the successful incorporation of tungsten atom into MFI framework and meanwhile possessed an enormous number of irregular mesopores ranging from 2 nm to 50 nm. The influence of TPAOH addition amount on the mesopore structure and properties of tungsten-doped MFI zeolite was further investigated. In addition, the crystallization process of tungsten-doped MFI zeolite sample was tracked and analyzed with SEM, XRD and BET characterizations, and accordingly possible formation process for hierarchical zeolite was proposed. Furthermore, the prepared hierarchical tungsten-doped MFI zeolite displayed eminent cyclohexene epoxidation performance and re-usability for more than five times. This work provides some guidance for the solvent-free synthesis of metallosilicate zeolites, decreasing the generation of wastewater and improving the zeolite yield.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2017
·
IF 2.843
Zhen Sun,Yueer Yan,Gang Li,Yahong Zhang,Yi Tang
A facile and fast microwave-assisted approach without any other pre/post-treatment has been proposed to hydrothermally synthesize six kinds of MFI-type heteroatom (Mn, Ga, Ti, Sn, Cr, Zr) zeolites. By comparing with oven heating mode, it is found that microwave field displays a positive effect on the introduction of partial heteroatoms in the zeolite framework. Moreover, differing from the conventional heating, microwave irradiation displays different influences on the different heteroatom zeolites because different heteroatoms cause different polarities and wave-absorption abilities of M–O bonds under microwave irradiation. Furthermore, this positive effect of microwave is embodied not only on heteroatom zeolite synthesis and heteroatom state in zeolite framework but also the resultant catalytic performance. This finding provides an easy route for the synthesis of novel heteroatom zeolite being difficult to prepare by conventional mode, along with a new direction for the exploration of microwave effect.
研究领域:
材料科学
·
化学工程
·
催化研究
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Molecular Catalysis
·
2026
·
IF 4.3
Hao Gu,Qiaoyun Qin,Ting Yang,Hongxia Liu,Jiayuan Yu,Jinfeng Wang,Changjiu Xia,Lei Liu
T4, T11, T10, and T8 are the most favorable Ti substitution sites in S-1. • In MFI-type zeolites, hydroxyl nest defects preferentially form at the T10-T1, whereas tripodal(1I) defects are most favorable at the T11-T10. • Compared with tripodal(1I) defects, the formation of hydroxyl nest defects is more sensitive to Ti incorporation and easily formed. • In TS-1, hydroxyl nest defects show stronger Lewis and Brønsted acidity compared with tripodal(1I) defects. Although MFI-type zeolites have been extensively studied, the formation of framework defects and their preferential siting at different framework positions remain difficult to accurately predict, which largely hampers the realization of defect engineering and precise defect control. In this study, density functional theory was used to study the preferred Ti substitution sites in S-1 zeolite. The results showed that T4, T8, T10, and T11 were the most favorable sites for Ti incorporation, and cluster models centered on these four representative sites were constructed as the main research objects to further analyze the formation sites and spatial distributions of hydroxyl nests and tripodal(1I) defects. These findings revealed that hydroxyl nest defects are most stable at Ti-T10-T1 sites in TS-1, whereas tripodal (1I) defects preferentially form at Si-T11-T10 sites in S-1, indicating that framework positions strongly affected the preference of defect site. Moreover, Ti incorporation markedly lowers defect formation energies, indicating that TS-1 is intrinsically more prone to defect formation than S-1, although the most stable defect configurations remain unchanged. Hydroxyl nest defects were more sensitive to Ti substitution, while tripodal(1I) defects were relatively unaffected. Furthermore, the optimal formation sites and acidity of two representative framework defects (hydroxyl nests and tripodal(1I) defects) in both S-1 and TS-1 were analyzed, and demonstrated that hydroxyl nest configurations in TS-1 exhibited stronger Lewis and Brønsted acidity. This study deepens the understanding of preferential framework defect sites and Ti substitution effects in MFI-type zeolites, providing theoretical guidance for defect-engineered design. Schematic illustration of the preferential formation sites of hydroxyl nest and tripodal(1I) defects in S-1/TS-1 and their Lewis and Brønsted acidity in TS-1. Download: Download high-res image (232KB) Download: Download full-size image
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