Acid sites modulation of siliceous-based mesoporous material by post synthesis methods

2021 ◽  
Vol 328 ◽  
pp. 111459
Author(s):  
Cristina Pizzolitto ◽  
Elena Ghedini ◽  
Somayeh Taghavi ◽  
Federica Menegazzo ◽  
Giuseppe Cruciani ◽  
...  
Keyword(s):  
Mesoporous Material ◽  
Acid Sites ◽  
Synthesis Methods ◽  
Post Synthesis

scholarly journals Hierarchical H-MOR Zeolite Supported Vanadium Oxide for Dimethyl Ether Direct Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 628 ◽  
Author(s):  
Wenfeng Wang ◽  
Xiujuan Gao ◽  
Ru Feng ◽  
Qi Yang ◽  
Tao Zhang ◽  
...  
Keyword(s):  
Vanadium Oxide ◽  
Pore Structure ◽  
Dimethyl Ether ◽  
Active Sites ◽  
Synthesis Method ◽  
Product Distribution ◽  
Acid Sites ◽  
Synthesis Methods ◽  
Direct Oxidation ◽  
Post Synthesis

A series of hierarchical H-MOR zeolites with different pore structure were designed and synthesized by alkaline and alkaline-acid post-synthesis methods. The catalytic performance of hierarchical H-MOR zeolite-supported vanadium oxide was investigated for dimethyl ether (DME) direct oxidation. Different pore structures apparently affect the distribution of oxidation product distribution, especially the selectivity of DMMx and CO. The formation of mesopores for 10%V2O5/deAlmm-H-MOR markedly improved the DMMx selectivity up to 78.2% from 60.0%, and more notably, CO selectivity dropped to zero compared to that of 10%V2O5/H-MOR. The hierarchical H-MOR zeolites were confirmed to be successfully prepared by the post-synthesis method. Due to the presence of mesoporous structure, the dispersion of vanadium oxide species was enhanced, which could improve the reducibility of vanadium oxide species and also make better contact with the acid sites of zeolite to exert the synergistic effect of the bifunctional active sites. More importantly, the creation of mesopores was proved to be favorable to the mass transfer of intermediate and products to avoid the occurrence of secondary reaction, which could effectively suppress the formation of by-products. This work is helpful for us to provide a novel insight to design the catalyst with suitable pore structure to effectively synthesize diesel fuel additives from DME direct oxidation.

A Novel Iron Silicate Mesoporous Material Synthesis and Its Characterization

2018 ◽  
Vol 24 (8) ◽  
pp. 5532-5536
Author(s):  
M. A Mary Thangam ◽  
Chellapandian Kannan
Keyword(s):  
Mesoporous Materials ◽  
Molecular Sieves ◽  
Mesoporous Material ◽  
Synthesis Method ◽  
Acid Sites ◽  
Mesoporous Molecular Sieves ◽  
Isomorphous Substitution ◽  
Main Role ◽  
Material Synthesis ◽  
Ft Ir

The mesoporous materials have variety of applications in several field particularly it has a main role in Catalysis, Petrochemical industries and Adsorption. Normally the porous material has well ordered 3Dimensional structure, huge surface area, high thermal stability and active acid sites. The properties of these materials can be varied because it is mostly depends on its template, synthesis method and isomorphous substitution of metal ions. There are two major mesoporous materials which are aluminosilicate and aluminophosphate. In this present investigation AlCl3 and FeCl3 are used in equal amount for the synthesis of mesoporous material. The synthesized material is characterized by FT-IR, XRD, TGA, BET, EDAX and TPD. Morphological images were studied by SEM. These characterization techniques confirm the formation of mesoporous molecular sieves.

scholarly journals Hybrid Organic-Inorganic Composite Materials for Application in Chemical Sensors

2009 ◽  
Vol 4 (2) ◽  
pp. 100-104
Author(s):  
Anca-Dana Bendrea ◽  
Ana-Maria Catargiu ◽  
Mircea Grigoras
Keyword(s):  
Chemical Sensors ◽  
Mesoporous Material ◽  
Oxidative Polymerization ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Chemical Oxidative Polymerization ◽  
X Ray ◽  
Post Synthesis ◽  
Inorganic Composite ◽  
Scanning Electron

Mesoporous SBA-15/conducting polymers composites, type SBA- polithiophene, SBA-polyaniline, respectively were synthesized and their physical properties were investigated. Polymers molecules were synthesized by chemical oxidative polymerization inside the pores of the mesoporous material by a post-synthesis process. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, thermal analysis and infrared spectroscopy.

High Dispersion Metal Oxide/Molecular Sieves: New Bifunctional Shape Selective Catalysts

1987 ◽  
Vol 111 ◽  
Author(s):  
R. Szostak ◽  
V. Nair ◽  
D. C. Shieh ◽  
T. L. Thomas
Keyword(s):  
Metal Oxide ◽  
Hydrothermal Treatment ◽  
Molecular Sieves ◽  
Oxide Phase ◽  
High Dispersion ◽  
Synthesis Methods ◽  
Highly Dispersed ◽  
Shape Selective ◽  
Oxide Particles ◽  
Post Synthesis

AbstractHighly dispersed metal oxide/molecular sieve catalysts can be prepared through modification of metallosilicate molecular sieves. The resulting materials have been shown to exhibit enhanced catalytic activities for selected reactions. The metallosilicates examined include the gallosilicates, iron (ferri-) silicates and cobalt silicates. The size of the metal oxide particles as well as their location (in the pores or on the surface) can be controlled through post-synthesis methods. Thermal or mild hydrothermal treatment of the metallosilicate produces a highly dispersed metal oxide phase, while higher temperatures or longer treatment causes the metal oxide to migrate and form larger agglomerates of the metal oxide phase. The size of these agglomerates are strongly dependent on the conditions of hydrothermal treatment. Dispersion, location and agglomeration of the metal oxide phase have been characterized for the iron silicates using both physical and catalytic techniques. The magnetic properties of the iron silicates are described.

2D-to-disguised 3D materials with built-in acid sites: H+-[Al]-RUB-18

2017 ◽  
Vol 46 (35) ◽  
pp. 11728-11737 ◽  
Author(s):  
Francisca S. O. Ramos ◽  
Heloise O. Pastore
Keyword(s):  
Acid Sites ◽  
Ethanol Dehydration ◽  
Hydrothermal Conditions ◽  
Tetrahedral Position ◽  
Synthesis Procedure ◽  
Post Synthesis

Al3+ heteroions have been incorporated into a Na-RUB-18 framework through a post-synthesis procedure under hydrothermal conditions. Characterization by 27Al NMR showed that aluminum is in tetrahedral position; the acidity present in the layers of the SiO2-pillared H+-[Al]-RUB-18 was probed by in situ ethanol dehydration monitored by FTIR.

scholarly journals Highly Active Aluminosilicates with a Hierarchical Porous Structure for Acetalization of 3,4-dimethoxybenzaldehyde

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Hartati Hartati ◽  
Didik Prasetyoko ◽  
Mardi Santoso ◽  
Hasliza Bahruji ◽  
Sugeng Triwahyono
Keyword(s):  
Porous Structure ◽  
Cetyltrimethylammonium Bromide ◽  
Strong Acid ◽  
Acid Sites ◽  
Synthesis Methods ◽  
Hierarchical Porous Structure ◽  
Highly Active ◽  
Hierarchical Porous ◽  
Strong Acid Sites ◽  
Wide Access

We report the synthesis of highly active mesoporous aluminosilicate for the acetalization of 3,4-dimethoxybenzaldehyde with propylene glycol. The existing synthesis methods for aluminosilicate and ZSM-5 were modified to produce aluminosilicate material with hierarchical porous structure. A combination of two structure directing agents, tetrapropylammonium hydroxide (TPAOH) and cetyltrimethylammonium bromide (CTAB), produced a highly active aluminosilicate framework that provides a wide access for bulky reactants and strong acid sites to catalyse the reaction. The pore structure and the strength of the acid sites were crucial for high conversion of 3,4-dimethoxybenzaldehyde.

scholarly journals Busting the efficiency of SAPO-34 catalysts for the methanol-to-olefin conversion by post-synthesis methods

2020 ◽  
Vol 28 (8) ◽  
pp. 2022-2027 ◽  
Author(s):  
Guoju Yang ◽  
Ji Han ◽  
Yujun Huang ◽  
Xiaoxin Chen ◽  
Valentin Valtchev
Keyword(s):  
Synthesis Methods ◽  
Olefin Conversion ◽  
Methanol To Olefin ◽  
Post Synthesis

The preparation of hierarchical SAPO-34 crystals via post-synthesis fluoride etching

2016 ◽  
Vol 52 (17) ◽  
pp. 3512-3515 ◽  
Author(s):  
Xiaoxin Chen ◽  
Aurélie Vicente ◽  
Zhengxing Qin ◽  
Valérie Ruaux ◽  
Jean-Pierre Gilson ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Mesoporous Material ◽  
Intrinsic Properties ◽  
Post Synthesis

SAPO-34 (CHA-type) was subjected to treatment with a mixed NH4F–HF aqueous solution resulting in a hierarchical micro-mesoporous material with retained intrinsic properties.

Mechanism of Creation and Destruction of Oxygen Interstitial Atoms by Nonpolar Zinc Oxide(10\bar{1}0) Surfaces

2021 ◽  
Author(s):  
Heonjae Jeong ◽  
Ming Li ◽  
Jingtian Kuang ◽  
Elif Ertekin ◽  
Edmund G Seebauer
Keyword(s):  
Zinc Oxide ◽  
Oxygen Vacancies ◽  
Semiconductor Devices ◽  
Synthesis Methods ◽  
Oxygen Interstitial ◽  
Interstitial Atoms ◽  
Post Synthesis

Oxygen vacancies (VO) influence many properties of ZnO in semiconductor devices, yet synthesis methods leave behind variable and unpredictable VO concentrations. Oxygen interstitials (Oi) move far more rapidly, so post-synthesis...

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