Catalysts
·
2023
·Vol. 13
·期 10
·1383
·
IF 3.9
Zhen Jiang,Liduo Chen,Yanhong Cui,Huijie Gao,Yisi Zhou,Wei Zhang,Yanhua Suo,Yingjun Wang
n-Alkane hydroisomerization over bifunctional catalysts is an effective approach for clean fuel production. However, achieving metal–acid synergy and enhancing the catalytic performance by the preparation of bifunctional catalysts with suitable proximity between the metal sites and Brønsted acid sites are still challenging. In this work, a series of Pt/SAPO-11 catalysts with different Pt loading applied inn-heptane hydroisomerization was synthesized. SAPO-11 was synthesized by the Instant Exactness Synthesis (IES) method, which, with unique morphology and pore structure, was chosen as support for the hydroisomerization catalysts; Pt/SAPO-11 was synthesized with the impregnation method, Pt nanoclusters with trace loading were fabricated over the SAPO-11 support, and the as-synthesized catalysts with different Pt loading were labeled as xPt/SAPO-11 (x = 0.1, 0.3, 0.5, 0.8 and 1.0). Various characterizations, including XRD, nitrogen adsorption–desorption, SEM, TEM, NH3-TPD and XPS, were carried out on catalysts to obtain deep insights into the microstructure and valence states of xPt/SAPO-11. The catalytic performance of xPt/SAPO-11, including catalytic selectivity and conversion, was investigated in then-heptane hydroisomerization in detail. Pt loading affected the catalytic properties of xPt/SAPO-11 in the hydroisomerization ofn-heptane. The selectivity of 0.5Pt/SAPO-11 toward isomers was about 65% with a conversion of 77% at 310 °C, which was obviously higher than other xPt/SAPO-11 catalysts.
研究领域:
催化化学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2022
·Vol. 97
·期 8
·2055-2067
·
IF 3.709
Xiaolong Liu,Jingye Ma,Minxin Wang,Hong Yuan
BACKGROUND A series of mesoporous Pt@KIT−6/SAPO−11 catalysts with SiO 2 :Al 2 O 3 molar ratios of 0.3, 0.4, or 0.5 and Pt loadings of 0.4, 0.8, or 1.2 wt% were prepared via an in situ encapsulation process using a PEO − PPO − PEO triblock copolymer (EO 20 PO 70 EO 20 , P123) as the mes. China 750001 oporous template and KIT−6 molecular sieves as the silicon source. RESULTS These catalysts were characterized by transmission electron microscopy (TEM), specific surface area analysis, and pyridine–infrared spectroscopy (Py − IR). The results showed that Pt nanoparticles with particle sizes of 3–7 nm were uniformly dispersed on the supports. These materials also exhibited good mesoporous structures with specific surface areas of 138–197 m 2 /g and average pore sizes of 7.1–9.9 nm. The specimens having a SiO 2 :Al 2 O 3 molar ratio of 0.4 also showed an orderly strip−shaped pore structure. The Py − IR results indicated that the catalysts had both Brønsted acid and Lewis acid sites, with total acid contents in the range of 77.8–131.1 μmol/g. CONCLUSION The decarboxylation of oleic acid using these materials under CO 2 was examined. The catalyst with a SiO 2 :Al 2 O 3 molar ratio of 0.4 and a Pt loading of 0.8 exhibited the best catalytic performance and a C8 − C17 alkanes yield as high as 85.1% at 340 °C by using a catalyst−to−oil mass ratio of 1:10 and a reaction time of 5 h. This performance was attributed to the ordered mesoporous structure of this catalyst along with its high surface area (173 m 2 /g), good crystallinity (92.8%), suitable acid content (98.6 μmol/g), and abundant Pt metal active sites. © 2022 Society of Chemical Industry (SCI).
研究领域:
催化化学
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材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2017
·
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
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 8
·4656-4666
·
IF 3.108
Zhou Chen,Wenjing Song,Shaohong Zhu,Weikun Lai,Xiaodong Yi,Weiping Fang
A dandelion-like SAPO-11 with multiple branches was fabricated by seed-induced steam-assisted conversion (SISAC), which combined an in situ inoculating seed method (in this case, the initial gel was pre-crystallized at 433 K for 24 h) and steam-assisted conversion (SAC) process. The dandelion-like SAPO-11 was fully crystalline and exhibited more acidity, external surface and mesopore volume compared with conventional hydrothermally crystallized SAPO-11, confirmed by Ar adsorption–desorption, pyridine-adsorbed infrared (Py-IR), 2,6-dimethylpyridine-adsorbed infrared (2,6-DMPy-IR) and NH3 temperature-programmed desorption (NH3-TPD). After loading Pt nanoparticles by incipient wetness impregnation, the morphological modification (benefiting from smaller nanobranches and introducing more external surface active sites) leads to enhanced heptane hydroisomerization activity of the dandelion-like Pt/SAPO-11 as great as 15.4% higher in comparison with a conventional Pt/SAPO-11 catalyst.
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
Frontiers in Chemistry
·
2022
·
IF 5.545
Dai Xiaojun,Cheng Yan,Si Meng,Wei Qiang,Zhou Yasong
The complexation-excessive impregnation modification method, which was original in this study, and the ion-exchange method and the in situ modification method were used to synthesize Ni-modified SAPO-11 molecular sieves. With the Ni-modified SAPO-11 samples as support, the corresponding NiWS-supported catalysts for the hydroisomerization of n-hexadecane were prepared. The effects of Ni-modification on SAPO-11 characteristics and the active phase were studied. The structure, morphology, and acidity of SAPO-11, as well as the interaction between active metals and support, the morphology, dispersibility, and stacking number of the active phase, were all changed by Ni-modification methods. The complexation-excessive impregnation modification method deleted a portion of Al from SAPO-11 molecular sieves while simultaneously integrating Ni into the skeletal structure of the surface layer of SAPO-11 molecular sieves, considerably enhancing the acidity of SAPO-11 molecular sieves. Furthermore, during dealumination, ethylenediaminetetraacetic acid generated more mesoporous structures and increased the mesoporous volume of SAPO-11 molecular sieves. Because the complexation-excessive impregnation modification method increased the amount of Ni in the surface framework of the SAPO-11 molecular sieve, it has weakened the interaction between the active phase and the support, improved the properties of the active phase, and greatly improved the hydroisomerization performance of NiW/NiSAPO-11. The yield of i-hexadecane of NiW/NiSAPO-11 increased by 39.3% when compared to NiW/NiSAPO-11. It presented a realistic approach for increasing the acidity of SAPO-11, reducing the interaction between active metals and support, and improving the active phase stacking problem.
研究领域:
催化
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化学工程
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材料科学
✓ 已验证
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Xiaojun Dai,Yan Cheng,Meng Si,Qiang Wei,Dongdong Chen,Wenbin Huang,Yasong Zhou
A series of SAPO-11 molecular sieves were synthesized in the concentrated gel system by reducing the water content in the synthesis system. With SAPO-11 molecular sieves as supports, NiW-supported catalysts were prepared for the hydroisomerization of n-hexadecane. SAPO-11 molecular sieves and catalysts were characterized by XRD, SEM, N 2 adsorption–desorption, NH 3 -TPD, Py-IR, HRTEM and XPS. The results showed that reducing the water content in the synthesis system could increase the mesoporous volume of SAPO-11 molecular sieve and improve the acidity of SAPO-11. For the corresponding catalysts, using SAPO-11 synthesized in concentrated gel system as the support weakened the interaction between the active phase and the support, and increased the dispersion and stacking number of the active phase, which effectively improved the catalytic performance of the catalyst. The yield of i-hexadecane of the catalyst NiW/45W-SA corresponding to SAPO-11 synthesized in conventional water content system was 28.14%, while that of the catalyst NiW/5W-SA corresponding to SAPO-11 synthesized in concentrated gel system was 52.24%. According to the distribution of isomers, it is inferred that hydroisomerization of n-hexadecane over NiW/SAPO-11 follows the pore-mouth mechanism.
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
Frontiers in Chemistry
·
2021
·
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
FUEL
·
2024
·
IF 6.7
Xiaojun Dai,Yan Cheng,Tingting Liu,Lingjuan Mao
The application of non-noble metal supported catalysts in the hydroisomerization of long-chain n-alkanes is a novel field, and there is currently not any research available on the deactivation process of these catalysts. We investigated into the deactivation mechanism of NiWS/SAPO-11 catalyst in the hydroisomerization of n-hexadecane in this work for the first time. Specifically, coke deposition behavior and active phase migration were investigated. The reduction of catalytic efficiency of the catalyst was partially aided by the decrease in specific surface area, pore volume, and acid density. From the perspective of the active phase, the clusters of NiWS active phase migrated as the reaction time increased, mostly resulting in an increase in both the stacking number and the length of active phase slabs. The migration of active phase increased the distance between active phase clusters and metal sites, and decreased the utilization ratio of active metal atoms. From the perspective of coke deposition, the coke formed on the catalyst includes soft coke and hard coke. The formation and evolution of coke on the catalyst were investigated. The soft coke (aliphatic compounds) progressively transformed into hard coke (polycyclic aromatic hydrocarbons and graphite-like), and the coke gradually migrated from the external surface of the catalyst to the pore channels as the reaction time increased. It is expected to provide theoretical basis and reference value for the deactivation research and design of non-noble metal supported hydroisomerization catalyst.
研究领域:
催化
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化学工程
·
石油化学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2023
·
IF 5.3
Xiaojun Dai,Yan Cheng,Tingting Liu,Lingjuan Mao,Qiang Wei,Yasong Zhou
SAPO-11 molecular sieves with different crystal sizes and particle sizes, especially nanosized small-crystal SAPO-11 molecular sieves, were successfully synthesized, and the corresponding NiWS-supported catalysts were prepared for the hydroisomerization of n-hexadecane. XRD, SEM, N2 adsorption–desorption, Py-IR, and HRTEM were used to analyze the effects of crystal size and particle size of the supports on their physicochemical properties, active phase properties, and catalytic performance of the catalysts. Through reaction evaluation and analysis of isomeric products, the effects of the size change of the support on the hydroisomerization performance of the catalyst and the hydroisomerization depth of n-hexadecane were determined. Through comprehensive analysis of the cracking products, it was determined that secondary cracking occurred when the conversion of n-hexadecane on the NiW/SAPO-11-S catalyst reached about 42.7%, and the secondary isomerization occurred when the conversion of n-hexadecane reached about 80%. The hydroisomerization reaction network of n-hexadecane over the NiWS/SAPO-11 catalyst was studied emphatically, and it was found for the first time that the secondary cracking of n-hexadecane during hydroisomerization followed the C3-β-scission mechanism.
研究领域:
化学工程
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催化
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材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 59
·34457-34464
·
IF 3.049
Lingmei Yang,Huiwen Li,Jun ying Fu,Ming Li,Changlin Miao,Zhongming Wang,Pengmei Lv,Zhenhong Yuan
In this article, a novel nano-rod-shaped SAPO-11 molecular sieve (SAPO-11-A-F) with a thickness of ca. 100 nm was successfully fabricated by the in situ seed-induced steam-assisted method using the cationic surfactant cetyltrimethylammonium bromide (CTAB) as a mesoporous template and a nonionic copolymer poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide), F127, as the crystal growth inhibitor. The fabricated nano-rod-shaped SAPO-11-A-F possessed nanocrystalline size, a hierarchical porous structure, and enhanced acidic sites. The added CTAB was mainly used to enhance the mesoporous structure and acid, and F127 acted as a grain growth inhibitor. According to the orientation growth mechanism of the molecular sieves, the crystallization mechanism of the nano-rod-shaped hierarchical porous molecular sieves with different crystallization times was investigated. It was found that the nano-rod-shaped molecular sieves were formed by the accumulation of nano-sheets. Compared to three nickel catalysts with different silicoaluminophosphate SAPO-11 molecular sieves in the hydroisomerization of oleic acid to iso-alkanes, the bifunctional catalyst of 7% Ni/SAPO-11-A-F had higher isomeric selectivity (79.8%); in particular, the isomeric octadecane showed stronger selectivity, indicating that the nano-rod-shaped SAPO-11 molecular sieve is more beneficial for the hydrodehydration reaction.
研究领域:
材料科学
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化学工程
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催化
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纳米技术
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2025
·Vol. 13
·期 36
·30599-30617
·
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.
✓ 已验证
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）