Hydrothermally Stable Ordered Mesoporous Titanosilicates with Highly Active Catalytic Sites

Xiao, Feng‐Shou; Han, Yu; Yu, Yi; Meng, Xiangju; Yang, Miao; Wu, Shuo

doi:10.1021/ja0170044

Cited by 207 publications

(137 citation statements)

References 34 publications

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“…In order to minimize diffusional limitations in the microporous network of MFI zeolites, several approaches have been developed in the last few years to induce intra-crystalline mesoporosity including hard templating [4][5][6], soft templating [7,8], demetalation [9][10][11][12][13][14][15] and modified crystallization methods [16,17]. Unfortunately, several of these approaches provide structures which are not hydrothermally stable in a manner similar to nanocrystalline zeolites.…”

Section: Introductionmentioning

confidence: 99%

Desilication of TS-1 zeolite for the oxidation of bulky molecules

Silvestre-Albero

Grau-Atienza

Serrano

et al. 2014

Catalysis Communications

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Highlights Desilication of TS-1 using NaOH gives rise to hierarchical zeolites.  Desilicated TS-1 exhibits a large BET surface area together with a well-developed mesoporosity.  Hierarchical TS-1 remains the activity of the original TS-1 for oxidation of small molecule.  Hierarchical TS-1 shows a significant improvement compared to original TS-1 for the oxidation of bulky molecules. AbstractA series of hierarchical TS-1 zeolites have been produced by desilication of the original TS-1 (4 wt.% Ti) using a chemical treatment with NaOH. Desilicated TS-1 zeolites exhibit a large BET surface area together with a well-developed mesoporosity. The hierarchical samples show good catalytic activity for the oxidation of small molecules while significantly higher activity for the oxidation of bulky molecules.

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Section: Introductionmentioning

confidence: 99%

Desilication of TS-1 zeolite for the oxidation of bulky molecules

Silvestre-Albero

Grau-Atienza

Serrano

et al. 2014

Catalysis Communications

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“…However, M41S materials generally exhibit weak acidity and low hydrothermal stability due to their amorphous frameworks. As a consequence, new synthesis strategies have been developed to obtain materials which com-bine the advantages of mesoporous materials and those of zeolites [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. For example, Corma et al [21] reported a post-synthesis dealumination process via steaming or acid leaching on full-grown zeolites.…”

Section: Introductionmentioning

confidence: 99%

“…Over the last couple of years, several simple and reliable approaches have been developed to form micro/mesoporous combined materials using zeolite nanoparticles or zeolite seeds as the silica source [31][32][33][34][35][36]. However, most of the published reports on composite catalysts have focused on one-dimensional materials (such as MCM-41 or SBA-15) as the mesostructured component, although three-dimensional materials, such as cubic MCM-48, are more interesting from the viewpoint of catalysis due to the interwoven pore system, which allows the sufficient diffusion of reactants within the pores, subsequently leading to a better catalytic performance [37].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of Pd/ZSM-5/MCM-48 biporous catalysts with superior activity for benzene oxidation

Cheng

et al. 2010

Applied Catalysis A: General

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a b s t r a c t ZSM-5/MCM-48 composite materials with different acidities and enhanced thermal stability have been synthesized via a simple and reliable in situ overgrowth method. The as-prepared biporous materials and the Pd-impregnated catalysts were systematically investigated by various techniques, including XRD, ICP-OES, N 2 adsorption/desorption, H 2 chemisorption, SEM, TEM/HRTEM, FT-IR, 27 Al MAS NMR, NH 3 -TPD, H 2 -TPR and XPS. The characterization results reveal that all composite catalysts exhibit high surface area, large pore volume and long pore diameter. The quantity of acid sites increases as the ZSM-5 additive amount increases, and Al atoms are in the tetrahedral coordination positions in composite materials. The activity tests demonstrate that all the Pd-loaded catalysts are active in the total elimination of benzene, while the catalytic activity values of Pd-loaded ZSM-5/MCM-48 composite catalysts are much higher than those of Pd/ZSM-5 or Pd/MCM-48 alone. Both Pd 0 and Pd 2+ are responsible for the oxidation reaction, and the catalytic activities are primarily related to the support acidity and the Pd dispersion. In addition, the stability of the composite catalysts also improves with an appropriate amount of ZSM-5 additives in MCM-48. This research shows that the novel Pd-loaded composite catalysts are promising materials in the elimination of VOCs.

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“…from the zeolitic nanoclusters which are present in the seed precursors of ZSM-5, TS-1(MFI with ~ 0.5 nm pore size) and zeolite beta (BEA with ~0.6 nm pore size), all synthesized under basic conditions. [12][13][14][15][16] Under neutral conditions and with non-ionic surfactants, aluminosilicate mesostructures with wormhole pore features were also synthesized using precursor mixtures of zeolites Y, ZSM-5 and Beta. 17 These materials exhibited hydrothermal stability, but showed low surface areas and small pore volumes.…”

Section: Iv-1 Backgroundmentioning

confidence: 99%

Improved Catalysts for Heavy Oil Upgrading Based on Zeolite Y Nanoparticles Encapsulated Stable Nanoporous Host

Ingram¹,

Mitchell²

2006

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Al-SBA-15 mesoporous catalysts with strong Brönsted acid sites and Al stabilized in a totally tetrahedral coordination was synthesized from the addition of hydrothermally aged zeolite Y precursor to SBA-15 synthesis mixture under mildly acidic condition of pH 5.5. The materials possessed surface areas between 690 and 850 m 2 /g, pore sizes ranging from 5.6 to 7.5 nm and pore volumes up 1.03 cm 3 , which were comparable to parent SBA-15 synthesized under similar conditions. Up to 2 wt. % Al was present in the most aluminated sample that was investigated, and the Al remained stable in totally tetrahedral coordination, even after calcination at 550˚C.The Al-SBA-15 mesoporous catalyst showed significant catalytic activity for cumene dealkylation, and activity increased as the amount of zeolite precursor added to the SBA-15 mixture was increased. The catalyst's activity was not affected by the aging time of the precursor for up to the 24 hr aging time investigated. This method of introducing Al and maintaining it in a total tetrahedral coordination is very effective, in comparison to other direct and post synthesis alumination methods reported. The catalytic performance of the zeolite Y/SBA-15 composite materials will be compared with that of pure SBA-15. The catalysts will then be evaluated for the conversion of heavy petroleum feedstocks.3 Table of Contents I ABSTRACT 2

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Hydrothermally Stable Ordered Mesoporous Titanosilicates with Highly Active Catalytic Sites

Cited by 207 publications

References 34 publications

Desilication of TS-1 zeolite for the oxidation of bulky molecules

Desilication of TS-1 zeolite for the oxidation of bulky molecules

Synthesis and characterization of Pd/ZSM-5/MCM-48 biporous catalysts with superior activity for benzene oxidation

Improved Catalysts for Heavy Oil Upgrading Based on Zeolite Y Nanoparticles Encapsulated Stable Nanoporous Host

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