JOURNAL OF POROUS MATERIALS
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2022
·Vol. 29
·期 5
·1387-1398
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IF 2.523
Ma Jingye,Liu Xiaolong,Yuan Hong
This work employed dodecyl trimethyl ammonium bromide, sodium dodecyl benzene sulfonate (SDBS) or dodecyl dimethyl betaine (BS–12) along with a PEO–PPO–PEO (P123) block copolymer to obtain a dual template system for catalyst synthesis. Using Pt(NH 3 ) 4 (NO 3 ) 2 as the platinum source, a series of mesoporous Pt/SAPO–11 catalysts with different Pt loadings were prepared via an in situ synthesis and characterized by X-ray diffraction, specific surface area analysis, temperature programmed desorption, X-ray photoelectron spectroscopy and transmission electron microscopy. These catalysts each had a complete AEL model structure with pore diameters in the range of 8.1–10.9 nm and specific surface areas between 103 and 168 m 2 /g. At a Pt loading of 1.0 wt%, the Pt/SAPO–11–S synthesized with SDBS–P123 as the dual template showed the least Pt loss, the largest specific surface area (159 m 2 /g) and the smallest Pt particle size (6.1 nm). This material also exhibited the highest ratio of Pt metal to oxide, indicating that it contained more active metal sites. This catalyst was applied to the decarboxylation of oleic acid under CO 2 to prepare C8–C17 alkanes, the main component of biological aviation kerosene. At a reaction temperature of 340 °C and catalyst-to-oil mass ratio of 1:10, the yield of C8–C17 alkanes reached 80.6% after 6 h. This same catalyst provided a 73.8% yield after six reuses, demonstrating good stability.
研究领域:
催化化学
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能源化学
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DOI
高影响因子
JOURNAL OF POROUS MATERIALS
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2024
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IF 2.5
Wang Chuangye,Liu Huili,Xue Jintang,Sun Ruixue,Song Xinrong,Zhang Xinyi,Zhang Longli
Introducing the second mesopores into SAPO-11 molecular sieve will be much helpful to improve the catalytic performance of its metal-supported catalysts in hydroisomerization of normal alkanes. In current paper, polyvinyl alcohol phosphates with different phosphorus contents were prepared and employed as mesopore template to prepare hierarchical SAPO-11. The effects of phosphorus content and concentration on the properties including mesopore structure, acidity and morphology of the prepared SAPO-11s have been investigated. The results showed that with appropriate phosphorus content and template concentration, PPVAs efficiently directed the generation of regular mesopore structure, extended the surface area and improved the acidity of the SAPO-11 molecular sieves. Pt/SAPO-11 bi-functional catalysts were prepared and their catalytic performances in hydroisomerization of n-hexane were evaluated. The highest conversion read 59.3%, while the optimal selectivity of branched hexanes was 86.5%.
研究领域:
催化材料
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化学工程
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2021
·Vol. 45
·期 38
·18070-18081
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IF 3.591
Xiaolong Liu,Jingye Ma,Hong Yuan
A series of mesoporous Pt@SAPO-11 catalysts with different Pt loadings were prepared using an in situ encapsulation process. These materials exhibited good topological structures and high Brunauer–Emmett–Teller (BET) surface areas (132–166 m2 g−1). Transmission electron microscopy images showed that the Pt nanoparticles in this material were in the 5–8 nm size range and were highly dispersed on the inner surfaces of the SAPO-11 support. N2-BET analyses demonstrated that the samples had mesoporous structures with average pore sizes of 7.3–8.5 nm. Characterization of the 1.0 wt% Pt@SAPO-11 catalyst by X-ray photoelectron spectroscopy and H2-temperature programmed reduction indicated strong interactions between the Pt nanoparticles and the carrier. This material was used to promote oleic acid decarboxylation under CO2 and gave a C8–C17 alkane yield of 80.8% after 4 h at 340 °C. After five repeated uses, the catalyst still gave a yield of 77.6%.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
ACS Omega
·
2019
·
IF 2.584
Lili Geng,Jianjun Gong,Guilong Qiao,Songshou Ye,Jinbao Zheng,Nuowei Zhang,Binghui Chen
Pt(NH3)4(NO3)2, Pt(NH3)4(Ac)2, (NH4)2PtCl4, and H2PtCl6 were used to prepare Pt/SAPO-11 catalysts to investigate the effect of Pt precursors on the hydroisomerization of n-dodecane. The catalyst derived from Pt(NH3)4(NO3)2 displays the best hydroisomerization activity and selectivity among these precursors. The hydroisomerization conversion of n-dodecane is affected by the platinum particle size, platinum dispersion, the location of platinum, and the valence state of platinum. The selectivity of n-dodecane is determined by the number of Brønsted acid sites and Pt crystal planes. These conclusions are verified by combining transmission electron microscopy, high-resolution transmission electron microscopy, hydrogen temperature programmed reduction, NH3-temperature programmed desorption, and Py-IR studies. The catalyst prepared with Pt(NH3)4(NO3)2 as the precursor exhibits the smallest platinum particle size and the highest platinum dispersion. Most of the platinum particles are supported on the external surface of SAPO-11 with the Pt(111) crystal face. Such a catalyst also possesses a suitable number of Brønsted acid sites and then displays the best catalytic performance. Obviously, the use of various precursors for the Pt-based catalyst can significantly affect the performance of Pt/SAPO-11 for the hydroisomerization of n-dodecane.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
Journal of Energy Chemistry
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2017
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IF 2.594
Zhichao Yang,Jilong Li,Yunqi Liu,Chenguang Liu
SAPO-11 molecular sieves were synthesized using silica sol, hydrophilic fumed silica , and tetraethyl orthosilicate (TEOS) as silicon precursors. Their physicochemical properties were characterized using XRD , SEM, nitrogen adsorption-desorption, Py-IR, NH 3 -TPD, EDS, and 27 Al, 31 P, 29 Si MAS NMR techniques. The catalytic performance was assessed in the hydroisomerization of n -octane. The results showed that the silicon precursors influenced the physicochemical properties and catalytic performance of SAPO-11. SAPO-11 synthesized using hydrophilic fumed silica as silicon precursor showed higher silicon distribution and had more medium acid sites. SAPO-11 synthesized using TEOS as silicon precursor had more silicon content , but more silicon islands formed in its framework. The depolymerization of silicon precursors might affect the silicon content and distribution in SAPO-11. In the hydroisomerization of n -octane, the catalytic activity strongly depended on the number of medium acid sites instead of the number of total acid sites. SAPO-11 synthesized using hydrophilic fumed silica as silicon precursor exhibited higher catalytic activity than the other samples because it has more medium acid sites.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
CATALYSIS TODAY
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2018
·
IF 4.667
Guanhua Xing,Siyang Liu,Qingxin Guan,Wei Li
This paper focused on the isomerization and cracking of n -alkanes to synthesize bio-jet fuel. A series of SAPO-11 supports with different Si/Al molar ratio (0.2, 0.4, 0.6) were prepared, characterized, and evaluated by the hydroisomerization on hydrodeoxygenation product of castor oil. As a result, a Ni-Mo/SAPO-11(0.4) catalyst with hollow tubular structure and moderate acidic strength exhibited optimum conversion (97.2%) and jet fuel selectivity (81.6%) in the reaction. Subsequently, Ni-Mo/SAPO-11(0.4) was selected to carry out further experiments on studying the hydroisomerization and hydrocracking of long chain n -alkanes. The results show that increasing temperature may promote hydroisomerization and hydrocracking. Temperature is more favorable for the reaction with the length of the carbon chain decreasing, no matter conversion, hydrocracking degree or isomerization tendency. The product selectivity of different n -alkanes is associated with the carbon number. In reaction to n -C 18 , Ni-Mo/SAPO(0.4) surpassed the other two catalysts in the conversion and i/n ratio at 623 K which is the optimum temperature.
研究领域:
催化化学
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能源科学
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DOI
高影响因子
Small Methods
·
2019
·Vol. 3
·期 5
·1800510
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IF 0
Dongxu Wang,Jiancong Liu,Xusheng Cheng,Xin Kang,Aiping Wu,Chungui Tian,Honggang Fu
The significant increase of catalytic efficiency while remaining low Pt usage is constantly pursued, but remains a challenge. Here, a “vacuum-assisted” (VA) process toward Pt clusters dispersed on SAPO-11 (S-11) is shown for a high-effective hydroisomerization of n -C 16 . The VA can make effective trapping of the Pt precursor on S-11 due to intensive capillary action, being conductive to stabilize and disperse Pt cluster (≈1 nm) on S-11 (V-Pt/S-11) for promoting synergy of Pt sites and acid sites on S-11. The test indicates excellent catalytic activity and stability of trace Pt clusters (0.15 wt%, even lower, 0.035 wt%) on S-11 (≈94.4% isomer selectivity at 94.3% conversion), much superior to I-0.15 wt% Pt/S-11 from traditional impregnation routes (≈88% selectivity at 90% conversion) and ever reported catalysts. The V-Pt/S-11 is also superior for the hydroisomerization of catalytic diesel oil with a decrease of freezing point up to 40 °C after hydroisomerization. The superior performance is attributed to the exposure of high acid density due to little coverage of Pt cluster on S-11, high dispersion of Pt leading to form more metal–acid bifunctional sites, and enhanced (de)hydrogenation ability of Pt clusters. All of them can promote the effective synergy of metal sites (Pt) and acid sites.
研究领域:
催化化学
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材料科学
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DOI
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
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产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Xiaojun Dai,Yan Cheng,Qiang Wei,Meng Si,Yasong Zhou
In order to prepare non-noble metal supported hydroisomerization catalyst with high catalytic performance, this work first proposed a novel three-stage crystallization method to synthesize small-crystal and hierarchical SAPO-11 molecular sieve, and prepared the corresponding NiWS supported catalyst for the hydroisomerization of n-hexadecane. The physicochemical properties of the small-crystal and hierarchical SAPO-11 molecular sieve and the NiWS supported catalyst were analyzed via a series of characterization methods. It was found that the crystal size of SAPO-11-S was reduced to 21.8 nm and the particle size was reduced to 70–140 nm. SAPO-11-S was superior to SAPO-11-C in pore properties and acidity. The reason for the increase of the number of medium-strong B acid sites in SAPO-11-S was investigated by 29 Si MAS NMR characterization, and the formation mechanism of SAPO-11-S was proposed by tracking and analyzing the crystallization process of SAPO-11-S. The decrease of crystal size of SAPO-11 molecular sieve effectively improved the sulfidation degree of active metals and the dispersion degree of the active phase of the catalyst, and promoted more active phases to form “type II active phase”. Compared with NiW/SAPO-11-C, NiW/SAPO-11-S showed higher catalytic activity and isomerization selectivity, and the maximum i-hexadecane yield of NiW/SAPO-11-S was 44.77% higher than that of NiW/SAPO-11-C.
研究领域:
催化
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化学工程
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材料科学
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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
·
催化
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DOI
高影响因子
Catalysis Science & Technology
·
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
·
纳米材料
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产品关联
DOI
高影响因子
Petroleum Science
·
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
危险品化学品经营许可证（带存储）