scholarly journals Synthesis of micro-mesoporous materials ZSM-5/FDU-12 and the performance of dibenzothiophene hydrodesulfurization

RSC Advances ◽  
2017 ◽  
Vol 7 (45) ◽  
pp. 28038-28047 ◽  
Author(s):  
Honglei Zhang ◽  
Longnian Han ◽  
Aijun Duan ◽  
Chunming Xu ◽  
Zhen Zhao ◽  
...  
Keyword(s):  
Mesoporous Materials ◽  
Molar Ratios ◽  
Assembly Method ◽  
Silica Source

The micro-mesoporous materials ZF-x (ZSM-5-FDU-12, x = SiO2/Al2O3) with different molar ratios of SiO2/Al2O3 were synthesized by an in situ nano-assembly method with the ZSM-5 precursor serving as the silica source.

scholarly journals Synthesis of Nb/MCM-48 material using rice husk ash as silica source with different SI/NB molar ratios

2021 ◽  
Vol 45 (171) ◽  
pp. 85-95
Author(s):  
Victor De Aguilar Pedott ◽  
Iemedelais Bordin ◽  
Carolina Elisa Demaman Oro ◽  
Ricardo Jorge Macieski ◽  
Diego Ivan Petkowicz ◽  
...  
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Nitrogen Adsorption ◽  
Structure Directing Agent ◽  
Alternative Source ◽  
Molar Ratios ◽  
Silica Source ◽  
In Situ Deposition ◽  
Adsorption Desorption

The large amount of rice produced in Brazil generates a large volume of co-products, such as, Rice Husk (RH) and Rice Husk Ash (RHA). These co-products have amounts of silicon (Si) present in their structure, which can be used to synthesize silica-based materials as zeolites and MCM-type structures. The synthesis of MCM-48 material was carried out at room temperature, using the ionic liquid [C16MI·Cl] as structure-directing agent, depositing the niobium in situ during the synthesis with different molar ratios of Si/Nb (5, 20, 50 and 80). The material obtained was subjected to characterization by X-Ray Diffraction (XRD), Nitrogen Adsorption/Desorption isotherms and Scanning Electron Microscopy (SEM). The results confirm the formation of Nb/MCM-48 materials, in which their properties are consistent with those described in the literature. The deposition of Nb on MCM-48 did not change its structural properties, such as specific surface area and pore distribution for Si/Nb higher than 5. The results obtained demonstrate the success in the synthesis of mesoporous materials Nb/MCM-48 using industrial residues of rice as an alternative source of silicon, and in situ deposition of the niobium metal on the structure.

scholarly journals Facile Preparation of Mesoporous MCM-48 Containing Silver Nanoparticles with Fly Ash as Raw Materials for CO Catalytic Oxidation

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 841
Author(s):  
Dong Tian ◽  
Yonghong Chen ◽  
Xiaoyong Lu ◽  
Yihan Ling ◽  
Bin Lin
Keyword(s):  
Silver Nanoparticles ◽  
Fly Ash ◽  
Co Oxidation ◽  
Surface Composition ◽  
Raw Materials ◽  
Silica Source ◽  
Co Conversion ◽  
Co Catalytic Oxidation ◽  
Adsorption Desorption

An environmentally friendly method was proposed to prepare mesoporous Mobil Composition of Matter No.48 (MCM-48) using fly ash as the silica source. Silver nanoparticles were infiltrated on MCM-48 facilely by an in situ post-reduction method and evaluated as an effective catalyst for CO oxidation. The as-prepared MCM-48 and Ag/MCM-48 nanoparticles were characterized by XRD, N2 adsorption/desorption, and TEM. Investigations by means of XPS for Ag/MCM-48 were performed in order to illuminate the surface composition of the samples. Studies revealed the strong influence of the loading of Ag nanoparticles on catalysts in the oxidation of CO. CO conversion values for Ag/MCM-48 of 10% and 100% were achieved at temperatures of 220 °C and 270 °C, respectively, indicating that the Ag-decorated MCM-48 catalyst is extremely active for CO oxidation.

Observation on the Structure of Ordered Mesoporous Materials at High Temperature via In Situ X-Ray Diffraction

2010 ◽  
Vol 132 ◽  
pp. 29-37
Author(s):  
Chun Fang Zhou ◽  
Jian Hua Zhu
Keyword(s):  
High Temperature ◽  
Mesoporous Materials ◽  
Pore Wall ◽  
Short Paper ◽  
Structure Variation ◽  
Ordered Mesoporous Materials ◽  
In Situ Xrd ◽  
Mesoscopic Structure ◽  
Xrd Patterns

This short paper reports the direct observation of the structure variation of mesoporous silica at temperatures higher than 600 oC by use of an in situ XRD technique. The mesostructure of SBA-15 or other mesoporous materials such as MCM-41 became almost invisible when the temperature rose to above 600 oC, but recovered or partially recovered once the temperature decreased. Contrarily, the characteristic XRD patterns of zeolites such as ZSM-5 kept unchangeable under the same conditions. On the basis of comparative experiments performed on various mesoporous samples, it is inferred that the reversible variation of XRD patterns probably originates from the thermal shock of the pore wall, not from the permanent collapse of the mesoscopic structure in these samples. This observation indicates the special features of SBA-15 at high temperature.

scholarly journals Colorless and Transparent Copolyimides and Their Nanocomposites: Thermo-Optical Properties, Morphologies, and Gas Permeabilities

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 585 ◽  
Author(s):  
Hyeon Shin ◽  
Young-Je Kwark ◽  
Jin-Hae Chang
Keyword(s):  
Optical Properties ◽  
Coefficient Of Thermal Expansion ◽  
Amic Acid ◽  
Gas Permeation ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Thermal Imidization ◽  
Organically Modified ◽  
Permeation Properties

A series of linear aromatic copolyimides (Co-PIs) were synthesized by reacting 4,4′-biphthalic anhydride (BPA) with various molar contents of 2,2′-bis(trifluoromethyl)benzidine (TFB) and p-xylylenediamine (p-XDA) in N,N′-dimethylacetamide (DMAc). Co-PI films were fabricated by solution casting and thermal imidization with poly(amic acid) (PAA) on glass plates. The thermo-optical properties and gas permeabilities of Co-PI films composed of various molar ratios of p-XDA (0.2–1.0 relative to BPA) were investigated. Thermal properties were observed to deteriorate with increasing p-XDA concentration. However, oxygen-transmission rates (O2TRs) and optical transparencies improved with increasing p-XDA concentration. Co-PI hybrids with a 1:0.2:0.8 molar ratio of BPA:TFB:p-XDA and organically modified hectorite (STN) were prepared by the in situ intercalation method. The morphologies and the thermo-optical and gas permeation properties of the hybrids were examined as functions of STN loading (5–50 wt %). XRD and TEM revealed substantial increases in clay particle agglomeration in the Co-PI hybrid films as the clay loading was increased from 5 to 50 wt %. The coefficient of thermal expansion (CTE) and the O2TR of a Co-PI hybrid film were observed to improve with increasing STN concentration; however, its optical transparency decreased gradually with increasing STN concentration.

scholarly journals In situ self-assembly of zirconium metal–organic frameworks onto ultrathin carbon nitride for enhanced visible light-driven conversion of CO2 to CO

2020 ◽  
Vol 8 (12) ◽  
pp. 6034-6040 ◽  
Author(s):  
Yanan Wang ◽  
Wenlong Zhen ◽  
Yiqing Zeng ◽  
Shipeng Wan ◽  
Haiwei Guo ◽  
...  
Keyword(s):  
Visible Light ◽  
Self Assembly ◽  
Carbon Nitride ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Assembly Method ◽  
Visible Light Driven ◽  
Metal Organic ◽  
Zirconium Metal

A series of Zr-porphyrin metal–organic framework (Zr-PMOF)/ultrathin g-C3N4 (UCN) heterostructure photocatalysts, as stable and efficient catalysts for the photoreduction of CO2, have been fabricated via a facile in situ hydrothermal self-assembly method.

scholarly journals Synthesis of High cis-Polybutadiene in Styrene Solution with Neodymium-Based Catalysts: Towards the Preparation of HIPS and ABS via In Situ Bulk Polymerization

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Ramón Díaz de León ◽  
Florentino Soriano Corral ◽  
Francisco Javier Enríquez-Medrano ◽  
Gabriela Bosques Ibarra ◽  
Patricia de León Martínez ◽  
...  
Keyword(s):  
Catalyst System ◽  
Bulk Polymerization ◽  
Activation Process ◽  
Morphological Development ◽  
Molecular Weights ◽  
Molar Ratios ◽  
Butadiene Polymerization ◽  
Melting Endotherm ◽  
Synthesized Materials

In a first step, 1,3-butadiene was selectively polymerized at 60°C in styrene as solvent using NdV3/DIBAH/EASC as the catalyst system. The catalyst system activation process, the addition order of monomers and catalyst components, and the molar ratios [Al]/[Nd] and [Cl]/[Nd] were studied. The catalyst system allowed the selective 1,3-butadiene polymerization, reaching conversions between 57.5 and 88.1% with low polystyrene contents in the order of 6.3 to 15.4%. Molecular weights ranging from 39,000 to 150,000 g/mol were obtained, while cis-1,4 content was found in the interval of 94.4 to 96.4%. On the other hand, the glass transition temperatures of synthesized materials were established in the range of −101.9 to −107.4°C, explained by the presence of polystyrene segments in the polybutadiene chains; in the same sense, the polybutadienes did not show the typical melting endotherm of high cis-polybutadienes. In a second step, the resulting styrene/high cis-1,4 polybutadiene solutions were used to synthesize ABS (adding a fraction of acrylonitrile monomer) and HIPS via in situ bulk polymerizations and the results were discussed in terms of morphological development, molecular parameters, dynamical mechanical behavior, and mechanical properties.

Alkali-hydrothermal synthesis and characterization of W-MCM-41 mesoporous materials with various Si/W molar ratios

2013 ◽  
Vol 270 ◽  
pp. 590-595 ◽  
Author(s):  
Hai-Yan Wu ◽  
Xiao-Li Zhang ◽  
Chun-Yan Yang ◽  
Xi Chen ◽  
Xiu-Cheng Zheng
Keyword(s):  
Hydrothermal Synthesis ◽  
Mesoporous Materials ◽  
Synthesis And Characterization ◽  
Molar Ratios ◽  
Mcm 41

scholarly journals Radially oriented mesoporous TiO2 microspheres with single-crystal–like anatase walls for high-efficiency optoelectronic devices

2015 ◽  
Vol 1 (4) ◽  
pp. e1500166 ◽  
Author(s):  
Yong Liu ◽  
Renchao Che ◽  
Gang Chen ◽  
Jianwei Fan ◽  
Zhenkun Sun ◽  
...  
Keyword(s):  
Single Crystal ◽  
Mesoporous Materials ◽  
High Performance ◽  
High Efficiency ◽  
Dye Sensitized Solar Cells ◽  
Building Blocks ◽  
Accessible Surface Area ◽  
Photoelectric Conversion Efficiency ◽  
Photoelectric Conversion ◽  
Assembly Method

Highly crystalline mesoporous materials with oriented configurations are in demand for high-performance energy conversion devices. We report a simple evaporation-driven oriented assembly method to synthesize three-dimensional open mesoporous TiO2 microspheres with a diameter of ~800 nm, well-controlled radially oriented hexagonal mesochannels, and crystalline anatase walls. The mesoporous TiO2 spheres have a large accessible surface area (112 m2/g), a large pore volume (0.164 cm3/g), and highly single-crystal–like anatase walls with dominant (101) exposed facets, making them ideal for conducting mesoscopic photoanode films. Dye-sensitized solar cells (DSSCs) based on the mesoporous TiO2 microspheres and commercial dye N719 have a photoelectric conversion efficiency of up to 12.1%. This evaporation-driven approach can create opportunities for tailoring the orientation of inorganic building blocks in the assembly of various mesoporous materials.

Preparation and Characterization of Ti-SBA-15 Mesoporous Materials with Varying Si/Ti Molar Ratios

2012 ◽  
Vol 482-484 ◽  
pp. 985-988
Author(s):  
Qiu Ying Huang ◽  
Wei Liu ◽  
Wen Hao Ye ◽  
Xiu Cheng Zheng
Keyword(s):  
Mesoporous Materials ◽  
Hydrothermal Process ◽  
Catalytic Efficiency ◽  
Mesoporous Structure ◽  
Catalytic Performance ◽  
Reaction Conditions ◽  
Molar Ratios ◽  
Good Catalytic Activity ◽  
Epoxidation Of Cyclohexene

Ti-SBA-15 mesoporous materials with different Si/Ti molar ratios were synthesized via a hydrothermal process and characterized by using various techniques. The effect of Si/Ti molar ratios in the gels on the structure and catalytic efficiency in epoxidation of cyclohexene was discussed in details. The results showed that all the Ti-SBA-15 materials retained SBA-15 mesoporous structure and exhibited good catalytic activity. Furthermore,the sample prepared with Si/Ti =50 exhibited the best catalytic performance under the reaction conditions.

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