JOURNAL OF SOLID STATE CHEMISTRY
·
2022
·
IF 3.656
Le Wang,Pengyu Niu,Hongjuan Xi,Xiaoyan Chen,Congbiao Chen,Zhongyi Ma,Litao Jia,Bo Hou,Debao Li
ZSM-22 zeolite with core-shell structure was synthesized via a facile one-pot/three-step synthesis route. The crystallinity , morphology, chemical composition , textural and acidic properties of core-shell ZSM-22 were characterized to reveal the formation mechanism in the crystallization process by various techniques, such as XRD , SEM, ICP , FTIR, Py-IR, N 2 -physisorption, and XPS analysis . The as-fabricated core-shell zeolites possess increased specific surface area (>150 m 2 g −1 ) and decreased Brønsted acid sites (81 μmol g −1 ). The acid sites located on the external surface of Al-rich zeolite nanocrystals were passivated by the epitaxy growth of high silica ZSM-22 shell. The size (radial dimension tune in the 30–65 nm range, axial dimension tune in 100–350 nm), structural properties, and acidity property of core-shell ZSM-22 can be adjusted freely by only modulating the alkalinity of the synthetic system in separate steps without adding silicon source and OSDAs. Moreover, it provides excellent tunability and controllability to both the size of products and the thickness of the Si-rich shell. The synthesis method herein may provide a generic platform for the design of other core–shell zeolites with potentially broader applicability.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Jingying Xu,Xuan He,Jiale Zhu,Xianqing Shao,Xuedong Zhu
The investigation of the synthesis of pure-phase ZSM-22 zeolites and their catalytic performance in the n-hexane cracking reaction is of critical significance for industrial production. To enhance the crystallinity of ZSM-22, ethylene glycol was integrated into the synthesis gel, effectively suppressing the formation of quartz and ZSM-5 impurities. Due to the structure-directing effect of ethylene glycol, the ZSM-22 prepared demonstrates much more mesopores compared to the counterparts without ethylene glycol addition. Furthermore, the acid strength and density of the zeolite increased significantly. These pure-phase ZSM-22 samples exhibited enhanced performance in terms of both conversion efficiency and ethylene selectivity during n-hexane cracking, which is associated with the increased abundance of acid sites and a higher ratio of strong to weak acids. These findings highlight the beneficial effects of ethylene glycol modification on the regulation of crystal growth and the enhancement of catalytic performance in ZSM-22 catalysts.
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
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 35
·16752-16763
·
IF 3.925
Kai Guo,Aizeng Ma,Zijian Wang,Jinzhi Li,Bingfeng Wu,Tong Liu,Dadong Li
The design of various hierarchical structures and morphologies of ZSM-22 zeolite catalysts is attempted through a post-treatment using different concentrations of NaOH and subsequently treating with HCl solution including fluosilicic acid (H2SiF6) and then loading Pt on their surfaces. The effects of samples on textural characters, acidity, as well as n-heptane catalytic hydroisomerization evaluation were examined. The formation process of the hierarchical structures was further investigated. Test and evaluation results indicated that samples treated with 0–0.5 M NaOH and subsequently treated with 6.0 M HCl and 0.1 M H2SiF6 were much more controllable and reasonable due to the better structure-activity relationship of the catalyst by changing crystal morphologies and introducing hierarchical structures. Indeed, PZH-0.3 exhibited 81.1% of the highest n-heptane conversion and 76.4% of total i-heptane yield in the n-heptane catalytic hydroisomerization process at 260 °C, PZH-0.5 displayed 13.6% of the maximum multi-branched i-heptane yield, which was above 104.1% in comparison with PZ-0 at 320 °C. Moreover, PZH-0.3 presented the highest n-butane yield, which possessed a proportion of 65.9% in the butane component of cracking products at 340 °C and improved an average of 16% and 22 times when utilizing PZ-0 and Pt/ZSM-5 catalysts. Additionally, the mechanism of the reaction process is briefly depicted according to the distribution of the reaction products. The regulation of zeolite both on crystal morphologies and pore hierarchy has obvious advantages in the hydroisomerization process, which can improve the composition of multi-branched isomers with high octane number effectively as well as supply raw materials for the chemical industry.
研究领域:
催化化学
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石油化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Chuang Liu,Jun Liang,Duozheng Ma,Xiangcheng Li,Liyuan Li,Yu Wang,Tiezhu Zhang,Wenhua Fu,Zhendong Wang,Weimin Yang
The synthesis of zeolite nanosheets is an effective strategy to obtain advanced catalysts with enhanced catalytic performance due to the improved diffusion properties. ZSM-22 zeolite nanosheets (F-ZSM-22, U-ZSM-22) with a controllable orientation and a thickness of less than 20 nm were obtained through hydrothermal crystallization by introducing NaF or urea into the synthetic system of conventional ZSM-22 (C-ZSM-22). In the presence of both NaF and urea, a zeolite nanosheet (FU-ZSM-22) with a decreased width was synthesized. In comparison with C-ZSM-22, all ZSM-22 nanosheets displayed better diffusion properties. On testing catalysts in the methanol-to-hydrocarbon reaction, ZSM-22 nanosheets showed better stability than C-ZSM-22, and FU-ZSM-22 was the best catalyst.
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
Catalysis Science & Technology
·
2017
·Vol. 7
·期 21
·5055-5068
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IF 5.773
Pengyu Niu,Hongjuan Xi,Jun Ren,Minggui Lin,Qiang Wang,Litao Jia,Bo Hou,Debao Li
Highly siliceous ZSM-22 was synthesized under hydrothermal conditions with ZSM-22 seeds. Characterization by FT-IR and 1H and 29Si NMR spectroscopy confirms that due to the existence of defective sites in the siliceous ZSM-22, acidic silanol groups including vicinal silanol and silanol nests are detected. Acidic silanol groups are considered as the acid sites of siliceous ZSM-22. As a result, siliceous ZSM-22 shows much lower acid site density and lower acid strength than silica–alumina ZSM-22 which contains hydroxyl groups bridging Si and Al as acid sites. In n-dodecane isomerization, Pt/siliceous ZSM-22 shows much higher isomer selectivity than Pt/silica–alumina ZSM-22. Furthermore, a lower loading amount of Pt on siliceous ZSM-22 (about 0.2 wt% Pt) can lead to high isomer selectivity. Owing to the acidic silanol groups and the low acid site density of siliceous ZSM-22, a good balance between metal and acid function in Pt/siliceous ZSM-22 is achieved, which results in a lower allowable Pt loading value and higher isomer selectivity.
研究领域:
催化化学
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材料科学
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石油炼制
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表面化学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2022
·Vol. 24
·期 39
·6987-6995
·
IF 3.756
Shujie Dai,Yangchun Tan,Yuhan Yang,Longfeng Zhu,Baogang Liu,Yanyan Du,Xuebo Cao
Organotemplate-free synthesis of zeolites assisted with zeolite seeds has been a hot topic in the past decade. Herein, we for the first time show an organotemplate-free synthesis of Al-rich S-ZSM-35 and S-ZSM-22 zeolites with the addition of ZSM-57 zeolite seeds. Notably, the adjustment of SiO2/Al2O3 and Na2O/SiO2 ratios in the starting gel to suitable values is an important factor in preparing the pure Al-rich S-ZSM-35 (Si/Al ratio at about 5) and S-ZSM-22 (Si/Al ratio at about 20) zeolites. The key to success is that the targeted ZSM-35 and ZSM-22 zeolite products have partly the same composite building units as the ZSM-57 zeolite seeds. The obtained Al-rich S-ZSM-35 and S-ZSM-22 zeolites show good crystallinity, typical crystal morphology, large BET surface area, and fully 4-coordinated aluminum species. In addition, as a typical example, the Al-rich S-ZSM-22 zeolite was evaluated by n-dodecane hydroisomerization reaction, which exhibits outstanding performance due to its Al-rich features (Si/Al ratio at about 20) compared with the conventional ZSM-22 zeolite (Si/Al ratio at about 30).
研究领域:
材料科学
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催化化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2018
·
IF 4.521
Pengyu Niu,Ping Liu,Hongjuan Xi,Jun Ren,Minggui Lin,Qiang Wang,Xiaoyan Chen,Litao Jia,Bo Hou,Debao Li
The formation of centrally branched iso-dodecane was controlled by absorption modes of alkene intermediates on ZSM-22, which included pore mouth type and key lock type. In this paper, we have designed and synthesized two kinds of ZSM-22 catalysts for selective formation of iso-dodecane with branched chain at more central positions from n -dodecane hydroisomerization. Aluminosilicate ZSM-22 was modified via carbonization of template to block the micropores and borosilicate ZSM-22 was synthesized. The characterization results and performance evaluation validated that micropore blockage could limit the pore mouth type at low reaction temperatures which favored the formation of iso-dodecane with side chain near the end of the carbon chain. Owing to the weak acid strength, higher temperatures, which favored the key lock mode, were needed to run the n -dodecane hydroisomerization over Pt/borosilicate ZSM-22. Both the two strategies for catalyst design achieved key lock adsorption mode and improvement of the selectivity for centrally branched iso-dodecane. Most importantly, weak acid sites on borosilicate ZSM-22 could catalyze double-bond isomerization reactions, which enhanced centrally branched iso-dodecane distribution up to more than 47%. Our research provides a prospective strategy for selective formation of centrally branched iso-alkanes and Pt/borosilicate ZSM-22 is expected to have potential applications in n-alkane hydroisomerization.
研究领域:
催化化学
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石油炼制
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材料化学
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工业化学
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能源化学
✓ 已验证
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2025
·
IF 3.4
Jinhui Song,Jiaxin Xie,Tianfu Zhang,Mengjiao Xing,Zimin Peng,Wenyao Gu,Jianyu Tang,Lu Tang,Suyao Liu,Yi Liu,Tong Chang,Yiwen Fang
Advancing the conventional hydrothermal and ionic liquid-assisted synthesis methodologies to produce ZSM-22 zeolites with similar characteristics yet notably distinct defect sites holds substantial significance in elucidating their influence on shape selectivity and hydroisomerization performance. This study investigated the impact of the initial gel ratio and synthesis parameters on the ionic liquid-assisted crystallization process and the crystal size of the ZSM-22 zeolite. The NH4F feed exhibits a minimal effect on the crystallization process, in contrast to the beneficial effect of improved ionic liquid and decreased water feed on substantially diminishing the crystal size of the resulting zeolites, which exhibit a morphology similar to that of the ZSM-22 zeolite obtained through the conventional synthesis route. Furthermore, the investigation into the crystallization process revealed that both ionic liquids and high temperatures play indispensable roles in accelerating the nucleation and crystal growth of ZSM-22 zeolite. When applied in the n-dodecane hydroisomerization, the nanosized ZSM-22 zeolites prepared by ionic liquid-assisted route exhibit remarkable isomer yield (above 72%), surpassing the conventional and large-size ZSM-22 zeolites. After the product distribution analysis, it is evident that the fewer Si–OH defect sites and the correspondingly strict confinement environment effectively limit the formation of the multibranched intermediates prone to crack, which ultimately improves the hydroisomerization performance, intrinsically reflecting the shape selectivity of the 10-membered ring zeolite by eliminating the interference of the framework defect sites. This work emphasizes the exceptional hydroisomerization performance of the ZSM-22 zeolite, highlighting the significance of its efficient synthesis and wide application.
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
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Le Wang,Pengyu Niu,Hongjuan Xi,Xiaoyan Chen,Congbiao Chen,Zhongyi Ma,Litao Jia,Bo Hou,Debao Li
The ZSM-22/ASA composite material for efficient hydroisomerization of n-dodecane was successfully prepared via a two-step synthesis method. The structure, pore properties, and acidity of the catalysts were elucidated by the means of XRD , N 2 physical adsorption, TEM, FT-IR, and Py-IR. Compared with the mixture catalyst, ZSM-22/ASA has a higher average pore diameter and formed a uniform and open channel structure, which is favorable to the diffusion of the reactant and the efficiency of the acid sites. The zeolite and the ASA phase in the composite are closely bonded by the interface effect, forming an additional Si–O–Al structure, which significantly affected the acidity of the composite catalyst. ZSM-22/ASA composite material exhibits enhanced n-dodecane hydroisomerization selectivity of total isomers and multi-branched isomers, which is attributed to its proper acid strength and pore structure conducive to diffusion. Finally, the location distribution of branched methyl groups was discussed and enhanced more central branching iso-dodecanes was obtained over the ZSM-22/ASA composite material.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Le Wang,Pengyu Niu,Hongjuan Xi,Xiaoyan Chen,Congbiao Chen,Zhongyi Ma,Litao Jia,Bo Hou,Debao Li
A facile method was developed to precisely control the particle size of nanosized ZSM-22 zeolite with a range of 80–850 nm via a two-step crystallization procedure. Based on the ZSM-22 crystallization process, inhibiting or promoting the crystal growth and the fusion of nanocrystals are crucial to obtain specific sized ZSM-22. For this purpose, the crystallization process of ZSM-22 was quenched after 12 h to obtain abundantly viable ZSM-22 nanocrystals formed on the aluminosilicate amorphous particles. In the recrystallization process, the viable nanocrystals continued to crystallize and the dissolved amorphous particles released Si and Al species as nutrients. After further simplifying the procedures, some additives were used at the very beginning of the recrystallization procedure. Not only small crystals can be formed but also the crystal length of ZSM-22 along the [001] direction varies from 80 to 850 nm. We have systematically investigated the influencing factors such as alkali metal cations and the alkalinity of the synthesis system on the mechanism of ZSM-22 zeolite nucleation and growth and the morphology and yield of products. We report a facile synthetic route for size-controlled nanosized ZSM-22 by decoupling its nucleation and growth processes for the first time.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Xiaoxian Li,Min Lin,Rui Li,Qiang Lu,Mingde Yang,Yulong Wu
In this work, methods employing ethanol for dispersion as well as precursor combination by rotary evaporation were combined to produce Ni-based ZSM-22 catalysts. The catalytic activity in palmitic acid deoxygenation over Ni/Z22@E was enhanced compared with that of the wet-impregnated method. The conversion of palmitic acid reached 98.9 %, in which C16/C15 alkane was as high as 4.07. The Ni species on the surface of catalysts showed strong stability so that not susceptible to inactivation by coking or leaching. In addition, the mechanism and kinetics of the palmitic acid deoxygenation reaction were analyzed. The results showed that the ethanol dehydration reaction was the most difficult to occur, and the high C 16 alkanes selectivity can be attributed to the low activation energy of the hydrodeoxygenation (HDO) pathway. Both experimental and kinetics calculation results suggested that there may be a mechanistic change in the fatty acid deoxygenation reaction at around 240 °C that resulted in a large increase in the hydrodecarboxylation (HDX) pathway. Based on this, selected adjustments of the products were proposed for fatty alcohols below 220 °C, C 16 alkanes between 260 and 280 °C, and C 15 alkanes above 280 °C.
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 35
·13967-13978
·
IF 3.069
Qiang Ning,Huaike Zhang,Yurong He,Zhiqiang Chen,Suyao Liu,Jie Ren
Small Pt particles (about 1.2 nm) were highly dispersed on ZSM-22 zeolites via a strong electrostatic adsorption (SEA) method and exhibited a promotion effect on the catalytic performance in n-dodecane isomerization in comparison with the conventional catalyst. Several promoters (Ce, La, and Re) were introduced to further improve the aggregation resistance of the small Pt particles. A series of characterization including H2-TPR, XPS and STEM as well as DFT calculations provided solid evidence that the strong interaction between Pt and promoter species not only effectively hinders the Pt aggregation but also alters the electronic state of the Pt sites. Moreover, Ce and La promoters also lead to a slightly improved amount of B acid sites determined by Py-FTIR. Thus, improved activity and selectivity were achieved on a Ce-modified catalyst due to the better balanced bifunctionality between the slightly increased acidity of zeolites and electron-deficiency of Pt. The electron-rich Pt sites are responsible for the significant increase of CH4 selectivity and the decrease of total isomer selectivity in n-dodecane isomerization. In addition, a high-temperature reduction test revealed the higher isomerization activity and selectivity (about 10% higher than the unmodified catalyst) of the Ce-modified catalyst owing to the strong bond of Pt–O–Ce, further confirming the positive effect of the Ce promoter on the sintering resistance of small Pt particles.
研究领域:
催化化学
·
材料科学
·
计算化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）