MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Shiqing Li,Xiaomeng Si,Rusi Peng,Huang Pan,Hao Xu,Jingang Jiang,Yanhang Ma,Peng Wu
Hierarchical Beta zeolite (named ECNU-41) was directly synthesized with commercially available ionic liquid 1-butyl-1-methylpyrrolidinium hydroxide as organic structure-directing agent (OSDA) in the absence of any surfactants or polymers. The ECNU-41 crystals were composed of nanorods through a unique stacking manner, exhibiting a morphology resembling the Chinese traditional toy “burr puzzle”. The orderly crisscrossed stacking ECNU-41 possesses high hydrothermal stability, abundant intercrystal mesoporosity, and enriched phase of polymorph B. In comparison to conventional nanosized Beta zeolites, ECNU-41 aluminosilicate and titanosilicate exhibited more remarkable and competitive catalytic performances in a variety of reactions, including benzene alkylation , methanol to propylene , and alkenes epoxidation. With improved diffusion rate and mass transfer due to the hierarchical structure, ECNU-41 is expected to serve as promising catalysts for those reactions involving bulky molecules.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
MOLECULES
·
2025
·Vol. 30
·期 7
·1457
·
IF 4.6
Fenfen Guo,Yuxuan Wang,Zhicheng Jiang,Youjing Tu,Ruikai Li,Xingyu Zhang,Aoyi Tang,Yuan Liang,Lishi Yan,Hu Luo,Shenggang Li,Lingzhao Kong
The catalytic production of lactic acid from carbohydrates was considered a green way to efficiently utilize renewable biomass resources. In this study, an easy post-synthesis method was used to prepare a Sn-Beta catalyst for the production of lactic acid from glucose at 180 °C, 2 MPa, and 30 min. With optimized reaction time, temperature, pressure, and the ratio of raw material to catalyst, the yield of lactic acid reached an astonishingly high level of 76.0%. In addition, the catalyst characterizations were performed in-depth, revealing the intrinsic relationship between catalyst performance and structure, proving that the 2 wt% Sn was uniformly dispersed in the skeleton of Beta zeolite, which significantly increased the density of Lewis acid. Thus, the enhanced isomerization and retro-aldol condensation processes over the Lewis acid sites led to the high yield of lactic acid. This catalytic system kept stable after five cycles at mild conditions, showing high potential for industrial biomass utilization.
研究领域:
生物化学
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催化化学
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产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Ling Zhang,Long Chen,Yaobin Li,Yuexin Peng,Fang Chen,Liang Wang,Changbin Zhang,Xiangju Meng,Hong He,Feng-Shou Xiao
For human health and environmental protection, removal of formaldehyde (HCHO) has become a hot topic, and completely catalytic oxidation at room temperature has been identified as one of the efficient routes for solving this problem. Recently, it has been reported that zeolite-supported Pt catalysts are active for HCHO oxidation at low temperatures, but they are still unable to completely oxidize HCHO at room temperature. To enhance the activity, it has been suggested to increase the Pt dispersion and acidic density in the zeolite-supported Pt catalysts. We therefore chose Al-rich Beta as a zeolite support because abundant aluminum species in the zeolite framework are advantageous for increasing acidic density through ion-exchange of protons and for improving Pt metal dispersion through the metal-zeolite interaction by increasing the negative charge of the zeolite framework with positively charged metal ions. As we expected, the Al-rich Beta zeolite supported platinum catalyst is very active, giving complete oxidation of HCHO at room temperature. To the best of our knowledge, this is the first time the complete oxidation of HCHO at room temperature over a zeolite-supported noble metal catalyst has been realized. In addition to its extraordinary activity, this catalyst is also very stable and selective. The strategy of designing zeolite-supported noble metal catalysts might offer an alternative way to develop highly efficient heterogeneous catalysts for the removal of air pollutants.
研究领域:
环境科学
·
催化化学
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产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2017
·
IF 4.636
Yuexin Peng,Ling Zhang,Long Chen,Dingzhong Yuan,Guoxiong Wang,Xiangju Meng,Feng-Shou Xiao
Catalytic combustion of toluene has been widely investigated due to importance of abatement of volatile organic compounds (VOCs), and in this work we have successfully prepared highly efficient heterogeneous catalysts for toluene combustion by impregnation of manganese oxides with Al-rich Beta zeolites (Beta-SDS) with H-form (MnO x /H-Beta-SDS) and K-form (MnO x /K-Beta-SDS) as well as pure siliceous Beta zeolite (MnO x /Si-Beta). Catalytic tests show that these zeolite-supported catalysts have higher activities than alumina-supported manganese oxides (MnO x /Al 2 O 3 ). By comprehensive consideration of reducibility, adsorbed oxygen species, and lattice oxygen species in the catalysts, it is shown that the adsorbed oxygen species play more important roles than others for the catalytic activity. The good catalytic performance and understanding of active sites over the MnOx/H-Beta-SDS might be helpful for preparation of catalysts in VOCs abatement.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
·
IF 4.9
Weimin Zhang,Wenming Hao,Yanni Guo,Jinghong Ma,Ruifeng Li
Even though cetyltrimethylammonium bromide (CTAB) has been successfully used in the surfactant-templating system to create the mesostructured zeolites , the formation mechanism of the pore structure still remains elusive. Here, we investigated the sol-gel and structure evolution in the hierarchical zeolite Beta synthesis focusing on the role of CTAB in a dual templating system. It is found that the induction period was prolonged and the Ostwald ripening was retarded by the presence of CTAB in crystallization . CTAB was involved in the synthesis and incorporated within the solid phase at the first stage when mesopores were formed. However, the incorporated CTAB was released later into the solution when the crystallized microporous structure was developed. The thermogravimetric analysis revealed that CTA + cation worked both as structure directing agent (SDA) for micropores and mesoporogen for the secondary lager pores in the matrix of hierarchical zeolite Beta. Moreover, CTA + competed with tetraethylammonium cation (TEA + ) to work as the SDA for micropores, with a decrease of the total amount of CTA + and TEA + when the concentration of CTAB in the synthesis solution was increased. It is anticipated that the understanding of the role of CTAB in the sol-gel and structure evolution in the hierarchical zeolite Beta synthesis process can provide a basis for designing the synthesis of hierarchical zeolites.
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Xiaolong Liu,Jiaxing Zhang,Xue Liu,Kaixuan Yang,Ting Su,Hongying Lü,Peng Wu,Zhiguo Zhu
Catalytic conversions of cyclic ketones into lactones by the Baeyer–Villiger oxidation are particularly attractive for practical applications because catalytic transformations minimize reactant use as well as waste production while simplify processing conditions. Understanding the unique behaviors of highly mesoporous Sn-Beta zeolite catalyst during Baeyer–Villiger oxidation is a challenging research topic. Herein, highly mesopore single-crystalline Sn-Beta zeolite (Sn-Beta-2s) is hydrothermally synthesized via our developed two-step interzeolite transformation strategy. The synthesis mechanism obeys dissolution–recrystallization process, where the degradation step is essential to prepare Sn-Beta-2s zeolite with abundant mesoporous and relatively high hydrophobicity. This single-crystalline Sn-Beta zeolite is adopted to the Baeyer-Villiger oxidation of cyclic ketones as heterogeneous Lewis acid catalyst. Structure-performance relationship reveals that the diffusion performance dominates the product selectivity over three Sn-Beta zeolites. Through the investigation of catalytic mechanism by in-situ FT-IR spectra and DFT calculations, it is found that carbonyl group is activated by zeolitic framework Sn. As for the bulky tert -butyl hydroperoxide oxidant, the reaction can be only triggered on the zeolite surface due to the severe steric constraints within zeolite channels, accounting for the excellent catalytic activity of Sn-Beta-2s zeolite with nanocrystalline nature.
研究领域:
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Zhipeng Qie,Zhaoqi Ji,Huan Xiang,Xinhan Zhang,Abdullah Alhelali,Lan Lan,Hassan Alhassawi,Guangbo Zhao,Xiaoxia Ou,Xiaolei Fan
Adsorption capacity of zeolitic adsorbents for organic pollutants can be affected severely under humid conditions and/or in aqueous systems. This study presents the development of hydrophobic Beta zeolites using a microwave-assisted post-synthetic treatment method (i.e., microwave-assisted chelation, MWAC) for adsorption removal of organics (benzene and phenol as the models) in aqueous systems. MWAC treatment enabled the dealumination of Beta zeolites in only one minute whilst increasing its hydrophobicity. Based on the characterization data, the mechanism for the hydrophobization of Beta zeolite was proposed. The influence of hydrophobicity, porosity and the property of organic molecules on adsorption behaviours were systematically studied, showing that the most hydrophobic Beta zeolite presented the highest benzene adsorption capacity per surface area of 2.87 × 10 −3 mmol/m 2 (at 1.0 g/L initial concentration). TGA and multi-cycle regeneration/adsorption experiments were employed to assess the regeneration and reusability of the adsorbents, and the results suggested that the modified Beta zeolites could be regenerated easily with the preserved physiochemical properties and adsorption capacity. The developed method and the associated zeolitic materials could be developed further for making high-performance hydrophobic zeolitic adsorbents for applications in organics removal from aqueous media.
研究领域:
环境科学
·
材料科学
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产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2023
·
IF 5.2
Caixia Miao,Meng Liu,Shengdong Tan,Guikai Zhang,Shengqi Chu,Shaojia Song,Qiyang Zhang,Jiaju Yu,Guiyuan Jiang,Weiyu Song,Qian He,Wenhao Luo,Zhijie Wu
Zeolite-tailored bimetallic Pt-Sn catalysts have been shown to be effective for propane dehydrogenation (PDH). Here, we have successfully prepared and compared two Sn-Beta-supported bimetallic PtSn catalysts (Pt/Sn-Beta (DG) and Pt/Sn-Beta (DA)), in which the Sn-Beta zeolite was prepared by a dry-gel (DG) synthesis method involving in situ Sn incorporation or a post-synthesis method involving dealumination and Sn incorporation (DA), respectively. The as-prepared Pt/Sn-Beta (DG), possessing a less fraction of extra-framework Sn species comparing to Pt/Sn-Beta (DA), shows a superior performance in terms of activity (TOF, 1.8 s -1 ), selectivity (99.0%) and stability (7360 min) at 550 °C using 40 kPa propane and 60 kPa nitrogen gas, reflecting one of the highest PDH performances for bimetallic Pt-Sn catalysts under similar conditions. By a combination of the state-of-the-art electron microscopy-based techniques and advanced spectroscopy techniques , we found that the proper Pt-Sn nano-alloying in Pt/Sn-Beta (DG), rather than Sn coverage on Pt species in Pt/Sn-Beta (DA) owing to the migration of excess extraframework Sn species, is essential for providing an enhanced PDH performance, as the active Pt species could be well isolated, accessed and stablized in Pt/Sn-Beta (DG) by alloying.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2024
·
IF 2.3
Dong Wenjie,Cai Ao,Wu Sui,Qi Beimeng,Dai Zhixi
A porous Sn–Er–Beta zeolite catalyst was rapidly prepared by introducing Sn source with water bath method and Er source with solid-state ion exchange method. When adding 180 mg catalyst, 225 mg glucose and 10 mL water into a reaction kettle at 200 °C for 2 h, the yield of lactic acid can reach 71.2%. After being recycled 5 times, the lactic acid yield of the catalyst can still reach 45.3%. The physical and chemical properties of Sn–Er–Beta zeolite were characterized, and it was confirmed that the catalyst had a multi-stage pore structure, with Sn and Er elements existing in the zeolite skeleton. Among them, the increase of Lewis acidity, Brønsted acidity and special strong alkaline sites of Sn–Er–Beta zeolite caused by the introduction of Sn, and the Lewis acidic sites are further increased after the introduction of Er. The combination of Sn and Er obviously improves the catalyst’s capability to catalyze glucose and fructose to produce lactic acid. This provides an important reference value for the directional catalytic process of sugars. Graphical abstract
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2021
·Vol. 28
·期 5
·1315-1324
·
IF 2.496
Cai Qiang,Yue Xiaoyang,Dong Wen-Sheng
Bimetallic modified Fe–Sn/Beta was synthesized and examined as a solid acid catalyst for the transformation of glucose into methyl lactate in methanol. The catalysts were characterized by a combined characterization techniques i.e. X-ray fluorescence spectroscopy, N 2 physisorption, powder X-ray diffraction, X-ray photoelectron spectroscopy, NH 3 temperature-programmed desorption, and pyridine adsorption Fourier transform infrared spectroscopy. A high yield of methyl lactate of 67% was achieved upon conversion of 0.3 g glucose in 24 g methanol over 0.15 g catalyst at 220 ℃ under 2 MPa N 2 for 6 h. The recyclability of the catalyst was also investigated, and the conversion of glucose remained constant; conversely, the yield of methyl lactate decreased slightly in five catalytic runs. The excellent catalytic performance of Fe–Sn/Beta was attributed to the presence of large amounts of Lewis acid sites. Besides, the rich mesoporosity in Fe–Sn/Beta improved mass transfer rates in the conversion of glucose to alkyl lactates.
研究领域:
催化化学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2018
·Vol. 8
·期 2
·73
·
IF 2.144
Yucun Cui,Zheng Yan,Mengli Li,Jie Zhu,Longfeng Zhu,Hong Yao,Xuebo Cao
We report a solvent-free synthesis of all silica Beta zeolite using a cheap organic template of tetraethylammonium bromide (TEABr). The method includes mixing, grinding and heating solid raw material in the absence of water solvent but the presence of zeolite seeds. The absence of water solvent significantly improves the efficiency of synthesis, while the addition of seeds remarkably enhances the crystallization rate. In addition, the use of a cheap organic template of TEABr greatly decreases the synthesis cost. The effects of the reaction compositions, including the molar ratios of NH4F/SiO2, TEABr/SiO2, and mass ratios of seeds to the silica, on the synthesis of the pure product were investigated using different temperature. Physicochemical characterizations, including XRD, SEM, TG and N2sorption, show that the zeolitic product has good crystallinity, uniform crystals, and high surface area.Keywords:zeolite;all silica Beta;solvent-free synthesis;tetraethylammonium bromide;cheap
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Yueqing Wang,Guoqiang Ding,Xiaohai Yang,Hongyan Zheng,Yulei Zhu,Yongwang Li
The selective synthesis of furfural or hydroxymethylfurfural (HMF) from fructose on single catalyst (Beta zeolite, Hβ) is challenging task. However, in this study, selectivity of Hβ zeolite was discovered easily to tune by solvent effects. Strong solvent effects on the selectivity of fructose conversion were observed in different manners depending on the solvent used. It was shown that the coordinated state of framework aluminum, induced by solvent effects, has a major impact on the selectivity. The solvents with amide group were discovered to induce the reversible tetrahedral-octahedral framework aluminum transformation, but the configuration of aluminum was no influenced by other solvents such as γ-butyrolactone (GBL). Compared with other solvents, the GBL was not able to enhance turnover frequency (TOF) value of reaction but also suppress the degradation of furfural. Interestingly, a considerable yield of furfural (50.25%) was obtained combined with tetrahedral and octahedral framework aluminum active sites in GBL, while high selectivity of HMF (83.3%) was achieved in presence of single tetrahedral framework aluminum over Hβ in NMP.
研究领域:
催化化学
·
绿色化学
✓ 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）