INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
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
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Lei Fan,Yuchao Lyu,Jianye Fu,Yupeng Tian,Furang Li,Wenjing Zhang,Xinmei Liu
The prominent size effects of metal nanoparticles (NPs) are mainly reflected in the change of electronic and geometric properties, which may induce distinct catalytic performance of the catalyst. Herein, Ni/SAPO-11 bifunctional catalysts with controllable sizes of Ni NPs were synthesized to investigate the particle size effects in n-hexane hydroisomerization. The results show that decreasing Ni particle size from 11.7 to 5.3 nm increases the concentration of surface Ni atoms and the proportion of low-coordinated Ni sites (corner, step sites) by 1.7 and 1.5 times, respectively. The low-coordinated surface Ni atoms have rich dangling bonds and high surface energy, resulting in greatly improved H 2 adsorption and activation abilities. Moreover, an increased proportion of low-coordinated Ni sites within the Ni cluster shifts the d-band center upward, further enhancing the adsorption and activation of reactants. The intrinsic catalytic activity (turnover frequency) of 5.3 nm Ni NPs is ca. 2 times as much as that of the 11.7 nm ones. Besides, the smaller Ni NPs enhanced the metal–acid synergy, leading to a higher selectivity to isomers. This work provides deep insights into the metal particle size effects over the bifunctional Ni/SAPO-11 hydroisomerization catalysts and can be extended to various metal supported catalysts.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Shiting Jia,Sai Geng,Mingming Han,Zhen Li,Bolin Zhao,Anyang Shi,Wenyu Xue,Jingyi Lao,Hailong Yu,Qiong Wu,Huihui Wang,Shiwei Liu
In the research of gas-phase Beckmann rearrangement reactions, the employment of modified molecular sieve catalysts has garnered significant research attention. However, the prevalent supported molecular sieve catalysts currently face two formidable challenges. First, the loaded catalytic species are susceptible to detachment, compromising the catalyst’s stability over time. Second, there is a pressing need to enhance the catalytic efficiency to cater to the requirements of modern, highly efficient catalytic processes. Employing a unique microenvironmental framework modification technique, this study has successfully synthesized a silicoaluminophosphate molecular sieve in situ boron doping on the AEL structure. The molecular sieve B-SAPO-11 exhibited a high specific surface area (195.71 m2/g) and enlarged micropore volume (0.065 cm3/g), providing abundant reaction sites and enhancing the efficiency of mass transport and diffusion, respectively, thus giving a favorable microenvironment for the reaction. The catalyst B-SAPO-11 showed an excellent catalytic performance in the gas Beckmann rearrangement reaction of cyclohexanone oxime. The reaction achieved a 96.5% conversion rate and 91.6% selectivity of the desired product under a weight hourly space velocity of 6 h–1 and a temperature of 400 °C. DFT calculations show that adding B forms a synergistic effect with Al, and the dual Bronsted acid catalysis reduces the reaction energy barrier (11.43 kJ/mol). This method has the advantages of high yield of the target product, rapid reaction, and easy catalyst recovery; a new idea was designed to prepare catalysts for gas-phase Beckmann rearrangement reactions.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 8
·3901-3908
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IF 3.925
Zhiping Chen,Li Liu,Faxiang Shi,Wenwu Zhou,Zhiyuan Yang,Anning Zhou
A series of hierarchical SAPO-11 molecular sieves synthesized by adding mesoporogens with different alkyl chain lengths were prepared. The synthesized hierarchical SAPO-11s were characterized by XRD, SEM, N2 adsorption–desorption, TEM, NH3-TPD and Py-IR. The results showed that the physicochemical properties of the hierarchical SAPO-11s change with the increase of the alkyl chain length, and the hierarchical SAPO-11 molecular sieve synthesized with DTAB has the largest external surface area and pore volume, and the most medium and strong B acid sites. Furthermore, the 1-octene hydroisomerization reaction on Ni catalysts supported on hierarchical SAPO-11 was investigated and the experimental results showed that the alkyl chain length of the mesoporogen has an obvious influence on the hydroisomerization selectivity. The hierarchical Ni/SAPO-11 catalyst synthesized using DTAB has the highest selectivity of C8 isomers and the lowest cracking selectivity. These results indicate that DTAB is the most suitable mesoporogen for the synthesis of hierarchical SAPO-11 molecular sieves for 1-octene hydroisomerization.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2013
·
IF 5.787
Lin Guo,Yu Fan,Xiaojun Bao,Gang Shi,Haiyan Liu
Silicoaluminophosphate (SAPO-11) samples with enhanced acidity were synthesized by two-stage crystallization in the presence of dodecyltrimethylammonium bromide (DoTAB), in which the Si source was added after the aluminophosphate framework was formed. The structure, elemental composition, acidity, Si environment, and n-octane di-branched isomerization of the as-synthesized SAPO-11 with small crystallites were investigated. The results showed that compared with the conventional one-stage crystallization, the two-stage crystallization produced more Si borders in the resulting SAPO-11. Among the SAPO-11 samples synthesized by two-stage crystallization, the SAPO-11 with the optimal DoTAB content (mol(DoTAB)/mol(SiO 2 ) = 0.015) had the most Si( n Al) (0 < n < 4) species with moderate and strong Brønsted acidity. The catalyst based on the small crystallite SAPO-11 containing a greater number of moderate and strong Brønsted acid sites exhibited superior performance for n-octane di-branched isomerization. This two-stage DoTAB-assisted crystallization opens a new route to enhancing the SAPO-11 acidity and can be extended to the other SAPO molecular sieves.
研究领域:
化学工程
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催化科学
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材料科学
✓ 已验证
DOI
高影响因子
Petroleum Science
·
2022
·
IF 4.757
Wei-Long Zhan,Yu-Chao Lyu,Xin-Mei Liu,Lei Fan,Fu-Rang Li,Ye Yang
The Ni/SAPO-11 catalyst used for n-hexane hydroisomerization was prepared via a novel two-step crystallization strategy. It involves introduction of nickel salt into the pre-crystalized system of SAPO-11 by grinding followed by a second crystallization step. No extra solvent is introduced during the whole synthesis procedure which reduces waste liquid emissions significantly. More importantly, interaction between nickel and support is effectively regulated by the novel method to achieve a well dispersed nickel species and inhibit formation of inert nickel spinel simultaneously. Chemical environments of framework Si are tuned to enhance surface acidity of the Ni/SAPO-11 catalyst. It also shows smaller particle size which favors fast diffusion of reactants and products. Insights into the two-step crystallization indicate that accumulation of SAPO-11 precursors in the pre-crystallization stage, pH regulation by nickel salt and structural directing effect of Ni 2+ during the second crystallization period account for the rapid crystal growth and smaller particle size of the Ni/SAPO-11 catalyst. All the unique features endow the Ni/SAPO-11 catalyst higher activity and isomers selectivity than the Pt/SAPO-11 catalyst in n-hexane hydroisomerization.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2013
·
IF 3.172
Yan Liu,Wei Qu,Weiwei Chang,Shuxiang Pan,Zhijian Tian,Xiangju Meng,Marcello Rigutto,Alexander van der Made,Lan Zhao,Xiaoming Zheng,Feng-Shou Xiao
Hierarchically porous SAPO-11 zeolite (H-SAPO-11) is rationally synthesized from a starting silicoaluminophosphate gel in the presence of polyhexamethylene biguanidine as a mesoscale template. The sample is well characterized by XRD, N 2 sorption, SEM, TEM, NMR, XPS, NH 3 -TPD, and TG techniques. The results show that the sample obtained has good crystallinity, hierarchical porosity (mesopores at ca. 10 nm and macropores at ca. 50–200 nm), high BET surface area (226 m 2 /g), large pore volume (0.25 cm 3 /g), and abundant medium and strong acidic sites (0.36 mmol/g). After loading Pt (0.5 wt.%) on H-SAPO-11 by using wet impregnation method, catalytic hydroisomerization tests of n -dodecane show that the hierarchical Pt/SAPO-11 zeolite exhibits high conversion of n -dodecane and enhanced selectivity for branched products as well as reduced selectivity for cracking products, compared with conventional Pt/SAPO-11 zeolite. This phenomenon is reasonably attributed to the presence of hierarchical porosity, which is favorable for access of reactants on catalytically active sites. The improvement in catalytic performance in long-chain paraffin hydroisomerization over Pt/SAPO-11-based catalyst is of great importance for its industrial applications in the future.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2020
·
IF 4.551
Yuxiang Liu,Wanrong Liu,Yuchao Lyu,Xinmei Liu,Jun Zhang,Yu Gu,Jiankun Huang,Svetlana Mintova,Zifeng Yan
A hierarchical SAPO-11 was prepared by a grinding synthesis method (GSM) and added as a promoter to increase the iso-paraffin yield of gasoline in fluid catalytic cracking (FCC) reaction. Compared to the classical hydrothermal method , the GSM leads to the creation of intra-crystalline mesopores with the assistance of a surfactant (Cetyltrimethyl Ammonium Bromide, CTAB). CTAB acts as a structure directing agent and as a hard template during the crystallization of SAPO-11. CTAB micelles formed the intra-crystalline mesopores in SAPO-11 crystals. The intra-crystalline mesoporosity of the SAPO-11 is preserved at 800 °C under steaming, which renders the material as an appropriate component of the FCC catalyst. Besides, the presence of mesopores provides isomerization active sites and accelerates the desorption of iso-paraffin. The mesoporous SAPO-11 showed a higher selectivity for iso-paraffin and the yield of iso-paraffin increased by 2%.
研究领域:
化学工程
·
石油加工
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Yongxin Ding,Jun Lin,Panjie Yu,Hongwei Zhang,Yongde Ma,Zhenping Cai,Yanning Cao,Kuan Huang,Lilong Jiang
The design of novel practical catalysts is critical for the blossoming of biodiesel green-energy, in which Mo-based catalysts are of particular interest. In this work, an in-situ synthesis method was proposed to obtain a combo Mo-based ionic liquid and SAPO-11 catalyst. The catalyst presents both highly dispersed MoS 2 as hydrodeoxygenation active sites and acidic sites for isomerization. MoS 2 with a few fine layers can be identified based on TEM images and the Brønsted acid sites are dominant based on Pyridine-IR analysis. A great performance of MoS 2 /C 8 min-15 %SA can be obtained under optimized reaction conditions with 100 % conversion of methyl palmitate, 75.0 mol% hydrodeoxygenation to n -C 15 -C 16 , and 20.5 mol % isomerization to i -C 15 -C 16 . The structure and activity of the catalyst can be retained at least for 4 cycles. Thin layers and high sulfurization, large amount of Brønsted acid sites, and suitable reaction conditions are key points to achieve a significant performance and avoid over cracking and deactivation. On basis of detected intermediates and kinetic data simulations, a complex reaction pathway was proposed and the specific k values for each elementary reaction were provided for the hydrodeoxygenation and isomerization of methyl palmitate.
研究领域:
催化化学
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绿色能源
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材料科学
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2024
·Vol. 11
·期 3
·036505
·
IF 1.8
Zhen Jiang,Liduo Chen,Yanhong Cui,Yanhua Suo,Wei Zhang,Yisi Zhou,Yingjun Wang
The monometallic Pt/SAPO-11 and bimetallic Ni-Pt/SAPO-11 catalysts were synthesized with Instant Exactness Synthesis (IES) method and characterized by XRD, nitrogen adsorption–desorption, SEM, TEM, FT-IR, Py-IR, NH3-TPD and XPS, and their properties were evaluated for the n-heptane hydroisomerization. The catalysts had spherical structure and moderate acid strength, and exhibited good n-heptane conversion and catalytic selectivity toward n-heptane isomers. Typically, Ni-Pt/SAPO-11 exhibited an isomer selectivity of 80.9% with a conversion of 69.9% at 310 °C, which was obviously better than Pt/SAPO-11 (isomer selectivity of 75.1% with a conversion of 60.6% at 310 °C). Moreover, the Ni-Pt/SAPO-11 catalyst displayed higher percentage of i-heptane (79%) and lower percentage of n-heptane (6%) than Pt/SAPO-11. The continuous test of 360 min indicated Ni-Pt/SAPO-11 catalyst had good catalytic stability. Bimetallic Ni-Pt alloy loaded on SAPO-11 had significantly effect on catalytic properties of n-heptane hydroisomerization.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2020
·Vol. 7
·期 8
·085009
·
IF 1.929
Wenjing Zhao,Hongxia Yang,Zhihui Li,Longli Zhang,Xufeng Lin,Hui Fu,Zhen Liu,Chuangye Wang
This work reports that the polyvinyl alcohol successfully templates the intracrystal mesoporous structure of hierarchical SAPO-11 molecular sieves. The structures of prepared hierarchical SAPO-11 materials and a conventional SAPO-11 simultaneously synthesized are characterized by X-ray diffraction, N2 adsorption/desorption, scanning electron microscopy and high resolution transmission electron microscopy. The characterizations demonstrate that this synthesized hierarchical SAPO-11 possesses a mesopore structure with a much regular pore size distribution. Importantly, these mesopores are intracrystal but not intercrystal. The bifuntional isomerization catalyst with this hierarchical SAPO-11 as support shows a high selectivity in hydroisomerization reaction of hexane, evidencing that the catalytic selectivity is improved by introduction of mesopore structure into the SAPO-11 crystal. The templating mechanism of polyvinyl alcohol in formation of mesopores is well discussed at the ending. This work provides a potential template to prepare hierarchical catalyst materials.
研究领域:
化学工程
·
材料科学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 45
·期 1
·169-178
·
IF 3.288
Lingmei Yang,Shiyou Xing,Wen Luo,Gai xiu Yang,Zhongming Wang,Pengmei Lv
Hydrogention of lipid to jet fuel especially iso-alkanes is considered as a promising technology to improve the cold-flow properties of bio-jet fuel. In this study, we successfully synthesized a hydroisomerization catalyst that is based on a SAPO-11 molecular sieve (SAPO-11-A-6) with a sea urchin-like and hierarchical porous structure. SAPO-11-A-6 was fabricated with an Al : cetyltrimethylammonium bromide (CTAB) ratio of 0.006 after pre-crystallization using an in situ seed-induced steam-assisted method (SISAC). The SAPO-11-A-6 molecular sieves exhibited abundant mesopores, a larger external surface area, and more acidic sites than SAPO-11-S molecular sieves without CTAB. After loading nickel nanoparticles by using a citric-acid-assisted impregnation method, the hydrogenation of oleic acid results indicated that among the series of Ni/SAPO-11 catalysts, a maximum of 78.2% isomer selectivity was achieved by the Ni/SAPO-11-A-6 catalyst under reaction conditions of 360 °C, 4 h, and 4.0 MPa H2. The crystal formation route of the sea urchin-like hierarchical porous SAPO-11 was proposed: after pre-crystallization, the cationic surfactant CTAB entered the layered semi-crystalline phase, contributing to the formation of the novel sea urchin-like mesoporous SAPO-11 structure.
研究领域:
材料科学
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催化化学
·
能源化工
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）