JOURNAL OF CATALYSIS
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2017
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IF 6.844
Chenglong Wen,Shanlei Han,Jundong Xu,Yu Fan
The article proposes a novel and eco-friendly method for synthesizing SAPO-11 in ethylene glycol (EG) and supercritical carbon dioxide (ScCO 2 ). The method incorporates ScCO 2 into EG to decrease the solubility of SAPO-11 precursors in EG and thereby forms a highly supersaturated solution of SAPO-11 precursors. The as-synthesized SAPO-11 possesses smaller particles, a larger external surface area, and a larger number of acid sites than the SAPO-11 synthesized in EG and the SAPO-11 synthesized in water and ScCO 2 , respectively. These advantages of the as-synthesized SAPO-11 endow the corresponding catalyst with superior dibranched isomer selectivity and low cracking selectivity during 1-octene hydro isomerization.
研究领域:
化学工程
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催化材料
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
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IF 3.8
Chuangye Wang,Jintang Xue,Ruixue Sun,Xinrong Song,Xinyi Zhang,Xufeng Lin,Longli Zhang
The purpose of this paper is to report an efficient templating synthesis of hierarchically porous SAPO-11 molecular sieves. Poly(vinyl alcohol) was phosphorylated to get different phosphorus contents, and those designedly modified polymers were employed as mesoporous template in the hydrothermal synthesis of SAPO-11. Consequently, the prepared hierarchical molecular sieves exhibited higher BET areas, regular mesopore structures, and better acidity than their conventional counterpart. The catalysts with SAPO-11s as support had improved catalytic conversion and selectivity in hydroisomerization of n-hexane. The templating mechanism of the designed mesoporogens as well as the effects of their phosphorus content on the properties of hierarchical SAPO-11 molecular sieves were well discussed. This work provides an effective approach to template intracrystal mesopores in hierarchical silicoaluminophosphate molecular sieves.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
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2017
·Vol. 52
·期 8
·4460-4471
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IF 2.599
Chen Zhou,Dong Yunyun,Jiang Shaoyang,Song Wenjing,Lai Weikun,Yi Xiaodong,Fang Weiping
Hierarchical SAPO-11 was successfully synthesized without a secondary template by changing the hydrothermal crystallization temperature. SAPO-11 with a larger external surface area, more acidity, and a large number of external active sites was constructed through a novel two-step crystallization strategy. Both precrystallization step and the low-temperature crystallization step were confirmed to be indispensable conditions for constructing hierarchical SAPO-11. After loading Pt nanoparticles by incipient wetness impregnation, the heptane hydroisomerizations based on 0.5 wt% Pt/C-SAPO-11-200 and 0.5 wt% Pt/T-SAPO-11-120 catalysts were carried out in a fixed-bed at a total pressure of 1.5 MPa with a H 2 /n-heptane volumetric of 400 and WHSV = 10 h −1 . A conversion level of 75.7% of 0.5 wt% Pt/T-SAPO-11-120 catalyst was reached, which was higher than that of 0.5 wt% Pt/C-SAPO-11-200 catalyst (64.3%) at 300 °C. The enhanced performance achieved was attributed to the improved effect of the support, in terms of not only better mass transport and higher number of exposure active sites but also improved dispersity and decrease in the size of Pt particles.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2012
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IF 6.002
Lin Guo,Xiaojun Bao,Yu Fan,Gang Shi,Haiyan Liu,Danjiang Bai
The structure, acidity, and n -octane di-branched isomerization of SAPO-11 synthesized with surfactants of different chain lengths in water–propanol system were investigated. The results showed that with the increasing chain length of surfactants, the crystallite size of SAPO-11 firstly decreased and then increased, but the external surface area and the active B acid sites of SAPO-11 firstly increased and then decreased. The smallest crystallite, the highest external surface area, and the most B acid sites were obtained simultaneously with the surfactant of 12 carbon atoms. The isomerization results of n -octane indicated that among the series Pt/SAPO-11 catalysts, the catalyst with DoTAB-directed SAPO-11 as support had the highest selectivity to di-branched isomers and the lowest cracking selectivity due to the largest external surface area that created more active sites to promote the formation of di-branched isomers by the key-lock mechanism and improve the diffusion of intermediates and products for reducing cracking reactions.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
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2018
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IF 3.956
Ping Zhang,Haiyan Liu,Yuanyuan Yue,Haibo Zhu,Xiaojun Bao
Hydroisomerization of light straight-chain paraffins to their branched isomers especially di-branched ones is considered as a promising technology to produce clean gasoline blending component with high octane number . In this article, we report a superior hydroisomerization catalyst that is based on a SAPO-11 molecular sieve (SAPO-11-H) simultaneously with smaller crystal size, hierarchical pore structure and enhanced acidity. This novel SAPO-11-H was successfully synthesized via a two-stage hydrothermal crystallization route by simultaneously using a cationic surfactant cetyltrimethylammonium bromide (CTAB) as template and a nonionic copolymer poly(ethylene oxide)‑ block ‑poly(propylene oxide)‑ block ‑poly(ethylene oxide) (F127) as crystal growth inhibitor . During the crystallization, CTAB plays roles in enhancing the acidity and creating the mesoporous structure, and F127 serves as a crystal growth inhibitor to control the crystals size. Compared to two Pt catalysts supported on a conventional SAPO-11 and a commercial SAPO-11, the SAPO-11-H supported Pt/SAPO-11-H catalyst with the same Pt loading (0.5 wt%) exhibited superior selectivity to di-branched C 8 isomers and dramatically lower cracking selectivity in n ‑octane hydroisomerization. The outstanding performance of Pt/SAPO-11-H is mainly attributed to two factors: one is the highly exposed pore mouths and hierarchical pore structure of SAPO-11-H that benefit the formation of di-branched isomers and avoid the cracking of the resultant di-branched isomers, and the other is the enhanced acidity that boosts the hydroisomerization activity.
研究领域:
化学工程
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催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
Petroleum Science
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2022
·
IF 4.757
Xue-Man Wang,Cheng-Long Wen,Yu Fan
Hierarchical SAPO-11 molecular sieve (ACS-11) was successfully synthesized employing the Al 2 O 3 /carbon (Al 2 O 3 /C) composite obtained through the pyrolysis of Al-based metal-organic framework (Al-MOF-96) as mesoporogen. Unlike other carbon-based mesoporogens with strong hydrophobicity, the Al 2 O 3 /C interacts with phosphoric acid and generates the AlPO 4 /C structure, which promotes the Al 2 O 3 /C dispersion in the synthesis gel of SAPO-11 and avoids the phase separation between them. The Al 2 O 3 /C as mesoporogen decreases the crystallite size of SAPO-11 via preventing the aggregation of SAPO-11 crystals. Additionally, the addition of Al 2 O 3 /C improves the Si distribution in the ACS-11 framework. Consequently, ACS-11 has smaller crystallites, more mesopores, and a greater amount of medium Brønsted acid centers than the conventional microporous SAPO-11 and the SAPO-11 synthesized using activated carbon as mesoporogen. The corresponding Pt/ACS-11 catalyst exhibits the maximal selectivity to multi-branched C 10 isomers (23.28%) and the minimal cracking selectivity (15.83%) in n-decane hydroisomerization among these catalysts. This research provides a new approach for preparing hierarchical silicoaluminophosphate molecular sieve-based catalysts to produce high-quality fuels.
研究领域:
催化材料
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化学工程
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燃料科学
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产品关联
DOI
高影响因子
ChemistrySelect
·
2024
·Vol. 9
·期 2
·e202304152
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IF 1.9
Xiaojun Dai,Yan Cheng,Tingting Liu,Lingjuan Mao
Graphical The effects of synthesis medium and synthesis conditions on the physicochemical properties of SAPO-11 molecular sieve were explored by combining the hydrothermal crystallization method with the fractional crystallization method. SAPO-11 molecular sieve has been widely used as the support of bifunctional catalyst for hydroisomerization of n-alkanes because of its mild acidity and unique one-dimensional pore structure, and has been widely used in industry. However, how to further improve and improve the physicochemical properties of SAPO-11 molecular sieve is still worth studying. In this work, fractional crystallization method was used to synthesize graded SAPO-11 molecular sieve. The effects of medium system, feed SiO 2 /Al 2 O 3 , crystallization time and crystallization temperature of the second crystallization process on the physicochemical properties of SAPO-11 molecular sieve were investigated from the perspectives of crystallinity, textural properties and acidity. The suitable synthesis medium and the best synthesis conditions were determined. It is expected to provide reference for the fractional crystallization synthesis of high performance SAPO-11 molecular sieve.
研究领域:
材料科学
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化学工程
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催化
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
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2017
·Vol. 7
·期 23
·5775-5784
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IF 5.773
Shuo Tao,Xiaolei Li,Guang Lv,Congxin Wang,Renshun Xu,Huaijun Ma,Zhijian Tian
The pore architecture and acidity of zeolite materials play crucial roles in the activity and selectivity of catalytic reactions. Herein, hierarchical SAPO-11 molecular sieve microspheres with uniform intercrystalline mesoporosity (ca. 4.3 nm) and tunable acidity were synthesized via dry-gel conversion (DGC) of a silicoaluminophosphate–organosilane composite. The products were comprehensively characterized using multiple techniques, including XRD, SEM, TEM, N2 adsorption–desorption, NH3-TPD, pyridine-adsorbed IR (Py-IR), TG and 29Si MAS NMR measurements. It is revealed that the products' acidity can be precisely tuned in a wide range by simply adjusting the water content used in the synthesis. The growth of such hierarchical SAPO-11 underwent a rearrangement of the mesopores: the original mesopores (ca. 17 nm) of the precursor were collapsed at the initial stage of crystallization and the final mesopores of the products were directed by the organosilane. More importantly, the Pt/hierarchical SAPO-11 catalysts exhibited enhanced isomerization selectivity in the hydroisomerization of n-dodecane, attributed to their excellent diffusion properties resulting from the hierarchical pore network. This work demonstrates a facile approach to synthesize hierarchical zeolites with tunable acidity, which is beneficial for catalytic reactions involving bulky molecules.
研究领域:
催化材料
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化学工程
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纳米材料
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产品关联
DOI
高影响因子
Frontiers in Chemistry
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2021
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IF 5.221
Dai Xiaojun,Cheng Yan,Si Meng,Wei Qiang,Zhao Luyuan,Wang Xiaohan,Huang Wenbin,Liu Haoran,Zhou Yasong
SAPO-11 molecular sieves were modified with different Ni contents by the in situ modification method. The Ni-modified SAPO-11 molecular sieves were used as the supports to prepare the corresponding NiW-supported catalysts for the hydroisomerization of n-hexadecane. The Ni-modified SAPO-11 and the corresponding NiW-supported catalysts were characterized by X-ray diffraction, scanning electron microscopy, N2 adsorption–desorption, NH3-temperature-programmed desorption, pyridine adsorbed infrared, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The results showed that Ni in situ modification preserved the crystal structure of SAPO-11; increased the BET specific surface area, mesopore volume, and medium and strong Brønsted acid amount of SAPO-11; and increased the stacking number of the active phase of the catalysts. 3Ni-SAPO-11 possessed the largest BET specific surface area, mesopore volume, and medium and strong Brønsted acid amount. NiW/3Ni-SAPO-11 possessed the highest dispersion of the active phase and the highest sulfidation degree of the active metals. The results of the hydroisomerization of n-hexadecane showed that Ni in situ modification improved the catalytic activity and selectivity of the catalysts for the hydroisomerization of n-hexadecane to varying degrees. Especially, NiW/3Ni-SAPO-11 had the highest catalytic activity and isomer selectivity, and the maximum yield of isomeric hexadecane could reach 71.18%.
研究领域:
催化
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材料科学
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化学工程
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2025
·Vol. 13
·期 36
·30599-30617
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IF 9.5
Xiaojun Dai,Tingting Liu,Lingjuan Mao,Zixuan Lv
In this work, a SAPO-11 molecular sieve was successfully synthesized via an alcohol–water solvent vapor-induced self-assembly conversion method for the first time. Compared with the conventional hydrothermal crystallization method, the alcohol–water solvent vapor-induced self-assembly conversion method used the induction of alcohol–water solvent steam to drive the solid nucleation and crystallization of the SAPO-11 molecular sieve xerogel precursor. SAPO-11 molecular sieves synthesized by the two methods were used as supports and loaded with NiWS active phase to prepare n-hexadecane hydroisomerization catalysts. The effects of the alcohol–water solvent vapor-induced self-assembly conversion method on the physicochemical properties of SAPO-11 were studied. Compared with the conventional hydrothermal crystallization method, the alcohol–water solvent vapor-induced crystallization method improved the pore structure and acidity of SAPO-11, promoted the dispersion of silicon species in SAPO-11, and inhibited Ostwald ripening during the formation of SAPO-11. The crystallization process of SAPO-11 synthesized via the alcohol–water solvent vapor-induced self-assembly conversion method was thoroughly investigated, and the mechanism of the crystallization was discussed. When SAPO-11 synthesized via alcohol–water solvent vapor-induced self-assembly conversion method was used as the support, the MSI of the catalyst weakened and the dispersion and stacking number of the sulfided active phase and the sulfidation degree of the active metals improved. The catalytic results of n-hexadecane hydroisomerization showed that SAPO-11 synthesized via the alcohol–water solvent vapor-induced self-assembly conversion method-based catalyst had higher catalytic activity and target product selectivity than the conventional SAPO-11-based catalyst. The catalytic kinetics of the catalysts were investigated in depth. The results showed that the metal site-acid site synergistic catalytic mechanism of SAPO-11 synthesized using the alcohol–water solvent vapor-induced self-assembly conversion method-based catalyst was better than that of the conventional SAPO-11-based catalyst. When SAPO-11 synthesized via the alcohol–water solvent vapor-induced self-assembly conversion method was used as the support, the hydroisomerization reaction path priority and hydroisomerization depth of the n-hexadecane hydroconversion over the catalyst improved and deactivation resistance was optimized. The approach is expected to provide a new route and reference for the synthesis of high-performance SAPO-11 molecular sieves and the design of high-efficiency hydroisomerization catalysts.
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Xiaohan Wang,Yasong Zhou,Zhiqing Yu,Qiang Wei,Haoran Liu,Jinxiao Sun,Wenbin Huang,Jinquan Tao,Meng Huang
A novel SAPO-11 molecular sieve with a lamellar structure and flower-like morphology was synthesized using cationic surfactant cetyltrimethylammonium bromide (CTAB) as the surfactant and KF as the mineralizer. Meanwhile, the effect of various CTAB additions on the structure and properties of SAPO-11 molecular sieves was also investigated. A number of characterization analyses’ findings reveal that, compared with conventional spherical SAPO-11 molecular sieves, flower-like SAPO-11 molecular sieves have the following advantages: (1) Flower-like SAPO-11 molecular sieves have open pores and larger mesopores, with suitable distribution of mesopores. (2) The prepared flower-like SAPO-11 molecular sieves have a lower total acid value but have a higher proportion of Brønsted acid sites, with suitable acidity. (3) The flower-like NiW/SAPO-11 catalysts have better dispersion of WS2 slabs and higher balance and proximity between metal sites and acid sites. The synthesized flower-like NiW/SAPO-11 showed significant isomerization performance and low cracking selectivity during the isomerization of n-hexadecane. When the conversion rate of n-hexadecane reached 77.0%, the yield of i-hexadecane was 59.4%.
研究领域:
化学工程
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材料科学
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催化
·
石油化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）