Regular HZSM-5 microboxes prepared via a mild alkaline treatment

Mei, Changsong; Liu, Zhicheng; Wen, Ping; Xie, Zaiku; Hua, Weiming; Gao, Zi

doi:10.1039/b805385e

Cited by 104 publications

(96 citation statements)

References 29 publications

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“…22-25 Enhanced diffusion ability and improved catalytic performance have been proven in alkaline-mediated mesoporous zeolites. [26][27][28][29][30][31] However, the efficiency of mesopore formation was found to depend on the nature of the base and the structural type of the zeolite framework. Bases such as NH 4 OH and Na 2 CO 3 were shown to be less effective than NaOH.…”

Section: Introductionmentioning

confidence: 92%

Hierarchization of USY Zeolite by NH₄OH. A Postsynthetic Process Investigated by NMR and XRD

et al. 2014

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Ammonia treatment of USY zeolite has led to a new hierarchical material. The local and global structural changes during the transformation have been monitored by XRD and by 1 H, 29 Si, and 27 Al solid-state NMR. A wealth of 1D and 2D NMR protocols were applied, including 1 H DQ-SQ, 27 Al MQMAS, 29 Si MAS and CPMAS as well as 1 H-29 Si HETCOR. The effects of aqueous ammonia treatment, different thermal post-treatments and rehydration were studied. An increasing loss of crystallinity was observed upon increasing duration of ammonia treatment. Under the experimental conditions a few percent of silica was lost into solution and no loss of aluminum was observed. But, increasing numbers of silanol groups were detected. The progressive transformation induces formation of mesopores, reduction of the fraction of the sample exhibiting Bragg crystallinity and apparition of a dense, amorphous aluminosilicate phase. The latter contains ammonium ions and strongly bound water which both are resistant to thermal decomposition up to 350 °C. After about 24 hours of treatment the zeolite fraction has been completely transformed into the amorphous phase. At intermediate stages a complexhierarchical material is obtained with mesopores and zeolitic micropores next to a dense amorphous aluminosilicate, containing ammonium ions, highly structured water and silanols nests.

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Section: Introductionmentioning

confidence: 92%

Hierarchization of USY Zeolite by NH₄OH. A Postsynthetic Process Investigated by NMR and XRD

et al. 2014

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“…To increase the efficiency of mentioned reaction in reduction of the aromatic compounds, many efforts have been made to develop solid acid catalysts . Recently, the interest in silica‐alumina with controlled porosity in the micro/mesoporous region as catalysts for various reactions has been increased . It seems that the micro/mesoporous composite materials with a hierarchical pore structure are a promising material in this catalytic reaction.…”

Section: Introductionmentioning

confidence: 99%

Ni‐W Catalysts Supported on HZSM‐5/HMS for the Hydrogenation Reaction of Aromatic Compounds: Effect of Ni/W Ratio on Activity, Stability, and Kinetics

Peyrovi

Parsafard

Hajiabadi

2017

Int J of Chemical Kinetics

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Ni‐W/HZSM5‐HMS catalysts were evaluated for the benzene hydrogenation reaction at 130–190°C. To study the catalyst characterization, X‐ray diffraction, X‐ray fluorescence, Fourier transform infrared, UV–vis, diffuse reflectance spectra, temperature‐programmed desorption of NH3, FT‐IR of adsorbed pyridine measurements (Py‐IR), H2 chemisorption, nitrogen adsorption–desorption, and TGA techniques were used. Kinetics of benzene hydrogenation was investigated under various hydrogen and benzene pressures, and the effect of reaction conditions on catalytic performance was studied. The results showed that bimetallic catalysts have better ability than a monometallic catalyst (Ni/HZSM5‐HMS) for this reaction, such as maximum benzene conversion (100%), minimum toluene conversion (1.76–40%), very low converted xylene, benzene selectivity (100%), good catalytic stability against coke deposition, and appropriate kinetic parameters.

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“…Herein, SAC and MAE have been demonstrated as effective routes to synthesize mesoporous zeolite structure (MZS) and hollow zeolite boxes, respectively. [56][57][58] The fabrication strategy of MZS involves two key steps: first, the meso-/micropore-structured zeolites with spherical morphology were synthesized under steaming; and subsequently, hollow core was created by selective mild desilication in the inner part of the spheres with aqueous Na 2 CO 3 solution, which finally leads to hollow mesoporous zeolite microspheres with uniform hollow architecture and unique mesoporous zeolite shells. Groen and coworkers 59 showed that by controlled desilication of both large and small ZSM-5 crystals they created hollow zeolite architectures.…”

Section: Template-free Strategymentioning

confidence: 99%

Synthesis and Catalytic Application of Zeolite-Based Hollow Materials

Li¹,

Zhang²,

Fang³

et al. 2014

energy environ focus

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Owing to the diffusion limitations of reactants and products in micropores, large zeolite crystals are not suitable for catalytic reactions involving macromolecules. Hierarchically porous zeolites with mesopores or macropores exhibit remarkably improved catalytic performance. Moreover, zeolite-based hollow structures are attracting a great deal of interest for their diverse applications in the areas of biochemistry, photonics, and catalysis. This review presents the fabrication and catalytic applications of the various zeolite-based hollow materials. The synthesis methods are classified to three categories, and the formation mechanisms were briefly summarized in this paper.

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Regular HZSM-5 microboxes prepared via a mild alkaline treatment

Cited by 104 publications

References 29 publications

Hierarchization of USY Zeolite by NH₄OH. A Postsynthetic Process Investigated by NMR and XRD

Hierarchization of USY Zeolite by NH₄OH. A Postsynthetic Process Investigated by NMR and XRD

Ni‐W Catalysts Supported on HZSM‐5/HMS for the Hydrogenation Reaction of Aromatic Compounds: Effect of Ni/W Ratio on Activity, Stability, and Kinetics

Synthesis and Catalytic Application of Zeolite-Based Hollow Materials

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Regular HZSM-5 microboxes prepared via a mild alkaline treatment

Cited by 104 publications

References 29 publications

Hierarchization of USY Zeolite by NH4OH. A Postsynthetic Process Investigated by NMR and XRD

Hierarchization of USY Zeolite by NH4OH. A Postsynthetic Process Investigated by NMR and XRD

Ni‐W Catalysts Supported on HZSM‐5/HMS for the Hydrogenation Reaction of Aromatic Compounds: Effect of Ni/W Ratio on Activity, Stability, and Kinetics

Synthesis and Catalytic Application of Zeolite-Based Hollow Materials

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Hierarchization of USY Zeolite by NH₄OH. A Postsynthetic Process Investigated by NMR and XRD

Hierarchization of USY Zeolite by NH₄OH. A Postsynthetic Process Investigated by NMR and XRD