JOURNAL OF CATALYSIS
·
2025
·
IF 6.5
Ping He,Huawei Geng,Lin Li,Qisong Yi,Lu Lin,Zhifeng Liu,Yuanshuai Liu,Valentin Valtchev
Solid acidic Al-MCM-41 materials are characterized by a high specific surface area and well-ordered hexagonally shaped mesopores. However, their relatively weak acidity compared to microporous zeolites significantly limits their practical applications in industrial catalytic reactions, particularly in upgrading biomass-derived organic feedstock that involves reactions with bulky molecules. Herein, we report a novel synthesis route for preparing acidity-enhanced Al-MCM-41 through the phase transformation of MWW-type zeolite precursors. The phase transformation approach markedly facilitates the incorporation of aluminum species into the MCM-41 framework, leading to strong Brønsted acidity of the resultant Al-MCM-41-T samples, as evidenced by comprehensive characterizations including 29 Si and 27 Al MAS NMR, NH 3 -TPD, and Py-IR. Owing to the enhanced acidity and its large pore structures, the as-prepared Al-MCM-41-T-15 sample (with Si/Al = 15) exhibited superior activity and selectivity toward C-alkylated products in both liquid-phase phenol-cyclohexanol and 4-cyclohexylphenol (4-CHP)-cyclohexene alkylation reactions compared the commercial Al-MCM-41-C with a similar Si/Al ratio. These findings afford an effective approach for preparing acidity-enhanced mesoporous solid acids, which hold significant potential for catalyzing lignin-derived bio-oils.
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
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
MACROMOLECULAR CHEMISTRY AND PHYSICS
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2017
·Vol. 218
·期 19
·1700236
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IF 2.5
Yulong Jin,Ning Zhao,Ruihua Cheng,Xuelian He,Zhen Liu,Boping Liu
The effects of sulfation on VO x /SiO 2 –MO y (M = Al, Zr, or Ti) are systemically studied for the synthesis of ultrahigh molecular weight polyethylene (UHMWPE), showing that the activity remains stable under the investigated polymerization temperature ( T p ) from 70 to 90 °C, and is almost doubled after sulfation. According to the results of NH 3 –TPD, pyridine-adsorption-fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), the enhancement effect in activity is likely related to the promoted acidity of the catalysts and the increased electron deficiency of the V center. Remarkable cocatalyst dependence is found and has the priority of diethylaluminum chloride (DEAC) > ethylaluminum sesquichloride > triisobutylaluminum > triethylaluminum, and the highest activity of 5200 kg PE mol −1 V could be obtained with DEAC as cocatalyst. The viscosity average molecular weight ( M v ) of the PEs can be regulated from 3 to 5 × 10 6 g mol −1 by decreasing T p from 90 to 70 °C. Based on the results of differential scanning calorimetry (DSC) annealing experiments, highly entangled UHMWPE is produced.
研究领域:
催化化学
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高分子材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2025
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IF 17.7
Ye Wang,Pan Gao,Dan Zhao,Tongrui Liu,Sitong Zhou,Miao Yang,Shiping Liu,Bing Li,Yida Zhou,Wenhao Cui,Guangjin Hou,Peng Tian,Zhongmin Liu
Silicoaluminophosphate (SAPO) molecular sieves possess diverse architectures and exceptional high-temperature hydrothermal stability, rendering them important acid catalysts. However, enhancing acid concentration of certain SAPO materials remains challenging, which limits their catalytic applications. Here, we report the synthesis of a series of SAPO materials using a developed SAPO precursor plus dual template (SPDT) strategy. A variety of SAPO materials characterized by high silica content and enhanced acidity, such as SAPO-34/56 intergrowths, SAPO-56, and SAPO-17, have been synthesized and thoroughly characterized using various techniques including integrated differential phase-contrast scanning transmission electron microscopy, two-dimensional solid-state nuclear magnetic resonance spectroscopy, and continuous rotation electron diffraction. The use of silica-enriched SAPO precursor combined with the flexible selection of the second template enables the crystalline phase regulation and improves the Si atoms incorporation into the framework. Notably, the synthesized SAPO-17 with abundant Si(4Al) species and unprecedentedly high acid density exhibits exceptional DeNO x activity after Cu loading, with NO x conversion exceeding 90% at 175–700 °C. This outstanding performance can be attributed to the unique ERI structure and the increased acidity of SAPO-17. This work not only presents an effective method for synthesizing SAPO molecular sieves with enhanced acidity but also offers a new perspective for expanding the active temperature range of the ammonia selective catalytic reduction reaction.
研究领域:
材料化学
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催化化学
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无机非金属材料
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环境催化
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分子筛科学
✓ 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）