scholarly journals R-Silsesquioxane-Based Network Polymers by Fluoride Catalyzed Synthesis: An Investigation of Cross-Linker Structure and Its Influence on Porosity

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1849 ◽  
Author(s):  
Nai-hsuan Hu ◽  
Joseph C. Furgal
Keyword(s):  
Surface Area ◽  
Environmental Remediation ◽  
General Structure ◽  
Synthesis Method ◽  
Porous Networks ◽  
Pore Size Distributions ◽  
Solvent Systems ◽  
Cross Linker ◽  
Post Synthesis ◽  
Synthesized Materials

Silsesquioxane-based networks are an important class of materials that have many applications where high thermal/oxidative stability and porosity are needed simultaneously. However, there is a great desire to be able to design these materials for specialized applications in environmental remediation and medicine. To do so requires a simple synthesis method to make materials with expanded functionalities. In this article, we explore the synthesis of R-silsesquioxane-based porous networks by fluoride catalysis containing methyl, phenyl and vinyl corners (R-Si(OEt)3) combined with four different bis-triethoxysilyl cross-linkers (ethyl, ethylene, acetylene and hexyl). Synthesized materials were then analyzed for their porosity, surface area, thermal stability and general structure. We found that when a specified cage corner (i.e., methyl) is compared across all cross-linkers in two different solvent systems (dichloromethane and acetonitrile), pore size distributions are consistent with cross-linker length, pore sizes tended to be larger and π-bond-containing cross-linkers reduced overall microporosity. Changing to larger cage corners for each of the cross-linkers tended to show decreases in overall surface area, except when both corners and cross-linkers contained π-bonds. These studies will enable further understanding of post-synthesis modifiable silsesquioxane networks.

Synthesis of Nanosiliceous Zeolite and its Functionalization with Silane Derivatives

2013 ◽  
Vol 62 (3) ◽  
Author(s):  
Norfariha Hassan ◽  
Zainab Ramli ◽  
Salasiah Endud
Keyword(s):  
Particle Size ◽  
Surface Modification ◽  
Hydrothermal Method ◽  
Surface Area ◽  
Crystal Morphology ◽  
Synthesis Method ◽  
Silanol Group ◽  
Bet Surface Area ◽  
Post Synthesis ◽  
Good Support

A nanosiliceous zeolite has been synthesized using hydrothermal method. Theoretically, nanosiliceous zeolite contains a lot of silanol group which allow the functionalization process for surface modification. Siliceous zeolite of the type silicalite (Sil) has been synthesized hydrothermally at 150°C for 4 days. The silicalite material was then functionalized with silane derivatives i.e 3–(triethoxysilyl)–propylamine (APTES), octadecyltrichlorosilane (OTS) and (3–mercaptopropyl)–trimethoxysilane (MPTS) using post–synthesis method. XRD results showed the formation of silicalite phase crystallinity. The FTIR result showed that Sil–OTS gave the highest intensity of the vibration assigned for silane derivative, followed by Sil–APTES and Sil–MPTS. The BET surface area of the functionalized–Sil decreased, showing the attachment of silane derivatives to silicalite has occurred. FESEM results showed sheet of hexagonal stick together to form granule–like crystal morphology of functionalized–Sil samples with larger particle size was observed for Sil–OTS, followed by Sil–APTES and Sil–MPTS after functionalization process. The functionalized–Sil sample is expected to be a good support for chemosensor molecules.

The effects of solvent viscosity on the morphology and photocatalytic activity of BiOBr catalysts

2021 ◽  
Author(s):  
Fengjuan Ge ◽  
Jie Zhu ◽  
Yan Xu ◽  
Jing Li ◽  
Xueyang Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Surface Area ◽  
Rhodamine B ◽  
Synthesis Method ◽  
Degradation Process ◽  
High Viscosity ◽  
Precipitation Method ◽  
Glycerol Solution ◽  
Solvent Viscosity ◽  
Degradation Tests

BiOBr photocatalysts were prepared by changing the solvent and synthesis method. SEM, XRD and BET characterization shows that the sample prepared in high-viscosity solution by precipitation method has tremella-like microstructure, with smaller size and higher surface area. Among them, the BiOBr prepared in glycerol solution (GR-P) has the highest surface area of 113.8 m2⋅[Formula: see text]. XRD also indicates that the GR-P has much more exposed (110) facets than other samples. The Rhodamine B degradation tests show that the GR-P has the best activity on both deethylation and aromatic ring destruction steps, indicating that the exposed (110) facets promote the degradation process.

scholarly journals Evaluating the Ability of Bone Char/nTiO2 Composite and UV Radiation for Simultaneous Oxidation and Adsorption of Arsenite

2022 ◽  
Vol 3 (1) ◽  
pp. 19-34
Author(s):  
Susan Alkurdi ◽  
Raed Al-Juboori ◽  
Jochen Bundschuh ◽  
Alla Marchuk
Keyword(s):  
Surface Area ◽  
Circular Economy ◽  
Pore Volume ◽  
Environmental Remediation ◽  
Titanium Dioxide Nanoparticles ◽  
Bone Char ◽  
Simultaneous Oxidation ◽  
Important Approach ◽  
High Level ◽  
Effect Of Surface

The reuse of waste materials for water treatment purposes is an important approach for promoting the circular economy and achieving effective environmental remediation. This study examined the use of bone char/titanium dioxide nanoparticles (BC/nTiO2) composite and UV for As(III) and As(V) removal from water. The composite was produced via two ways: addition of nTiO2 to bone char during and after pyrolysis. In comparison to the uncoated bone char pyrolyzed at 900 °C (BC900), nTiO2 deposition onto bone char led to a decrease in the specific surface area and pore volume from 69 to 38 m2/g and 0.23 to 0.16 cm3/g, respectively. However, the pore size slightly increased from 14 to 17 nm upon the addition of nTiO2. The composite prepared during pyrolysis (BC/nTiO2)P had better As removal than that prepared after pyrolysis with the aid of ultrasound (BC/nTiO2)US (57.3% vs. 24.8%). The composite (BC/nTiO2)P had higher arsenate oxidation than (BC/nTiO2)US by about 3.5 times. Arsenite oxidation and consequent adsorption with UV power of 4, 8 and 12 W was examined and benchmarked against the composite with visible light and BC alone. The highest UV power was found to be the most effective treatment with adsorption capacity of 281 µg/g followed by BC alone (196 µg/g). This suggests that the effect of surface area and pore volume loss due to nTiO2 deposition can only be compensated by applying a high level of UV power.

scholarly journals Synthesis and characterization of Mo2 C based materials over activated carbon derived from sewage sludge pyrolysis for catalytic applications

Cerâmica ◽  
2018 ◽  
Vol 64 (370) ◽  
pp. 148-155
Author(s):  
A. C. Alexandrino ◽  
J. F. de Sousa ◽  
C. P. de Souza ◽  
C. P. B. de Araújo ◽  
M. V. M. Souto
Keyword(s):  
Sewage Sludge ◽  
Surface Area ◽  
Synthesis Method ◽  
Metal Catalyst ◽  
Catalytic Material ◽  
Metal Support ◽  
Size Evaluation ◽  
Adsorption Desorption ◽  
Substitute Materials

Abstract Transition metal carbides have been successfully used as substitute materials for conventional noble metal catalyst in several important industrial reactions due to their interesting physicochemical properties. Surface structure, chemical composition and metal-support interactions, as well as processing conditions, are of utmost importance in the use of such materials in catalysis. The present study aimed to synthesize and evaluate pure molybdenum carbide with and without support, and bimetallic Mo-Ni carbide over a carbon active support derived from sewage sludge pyrolysis. The support was chemically (KOH) and physically (thermal treatment) activated before use. TG/DTG, XRD, XRF, SEM, BET and particle size evaluation were performed, together with adsorption/desorption isotherms. Results indicated that the applied synthesis method was adequate for the obtainment of pure materials. The increase in surface area of the support was significant, from 13 to 141 m².g-1 after the thermal and chemical treatment; also, supporting Mo2C over carbon provided an increase from 45 to 73 m².g-1 in surface area, which indicated its potential as a catalytic material as well as the effectiveness of the applied methodology.

scholarly journals Straightforward Immobilization of Phosphonic Acids and Phosphoric Acid Esters on Mesoporous Silica and Their Application in an Asymmetric Aldol Reaction

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 249 ◽  
Author(s):  
Christian Weinberger ◽  
Tatjana Heckel ◽  
Patrick Schnippering ◽  
Markus Schmitz ◽  
Anpeng Guo ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Phosphoric Acid ◽  
Surface Area ◽  
Aldol Reaction ◽  
Synthesis Method ◽  
Mesoporous Silicas ◽  
Phosphonic Acids ◽  
Asymmetric Aldol ◽  
Asymmetric Aldol Reaction ◽  
Acid Esters

The combined benefits of moisture-stable phosphonic acids and mesoporous silica materials (SBA-15 and MCM-41) as large-surface-area solid supports offer new opportunities for several applications, such as catalysis or drug delivery. We present a comprehensive study of a straightforward synthesis method via direct immobilization of several phosphonic acids and phosphoric acid esters on various mesoporous silicas in a Dean–Stark apparatus with toluene as the solvent. Due to the utilization of azeotropic distillation, there was no need to dry phosphonic acids, phosphoric acid esters, solvents, or silicas prior to synthesis. In addition to modeling phosphonic acids, immobilization of the important biomolecule adenosine monophosphate (AMP) on the porous supports was also investigated. Due to the high surface area of the mesoporous silicas, a possible catalytic application based on immobilization of an organocatalyst for an asymmetric aldol reaction is discussed.

Effects of Synthesis Conditions on the Crystalline Phases and Photocatalytic Activities of Silver Vanadates via Hydrothermal Method

2009 ◽  
Vol 1171 ◽  
Author(s):  
Chao-Ming Huang ◽  
Guan T. Pan ◽  
Lung C. Chen ◽  
C.K. Thomas Yang ◽  
Wen S. Chang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Surface Area ◽  
Synthesis Method ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Synthesis Conditions ◽  
Vis Spectroscopy ◽  
Visible Light Driven

AbstractVisible-light-driven Ag3VO4 photocatalysts were successfully synthesized using low-temperature hydrothermal synthesis method. Under various hydrothermal conditions, the structures of silver vanadates were tuned by manipulating the hydrothermal time and the ratio of silver to vanadium. X-ray diffraction (XRD) results reveal that the powders prepared in a stoichiometric ratio consisted of pure α-Ag3VO4 or mixed phases of Ag4V2O7 and α-Ag3VO4. With increasing the Ag-to-V mole ratio to 6:1, the resulting samples were identified as pure monoclinic structure α-Ag3VO4. UV-vis spectroscopy indicated that silver vanadate particles had strong visible light absorption with associated band gaps in the range of 2.2-2.5 eV. The sample synthesized in the excess silver exhibited higher photocatalytic activity than that synthesized in a stoichiometric ratio. The powder synthesized at silver-rich at 140℃ for 4 h (SHT4) exhibited the highest photocatalytic activity among all samples. The reactivity of SHT4 (surface area, 3.52 m2 g-1) on the decomposition of gaseous benzene was about 16 times higher than that of P25 (surface area, 49.04 m2 g-1) under visible light irradiation. A well developed crystallinity of Ag3VO4 of SHT 4 was considered to enhance the photocatalytic efficiency.

High surface area submicrometer-sized β-SiC particles grown by shape memory synthesis method

2005 ◽  
Vol 14 (8) ◽  
pp. 1353-1360 ◽  
Author(s):  
Nicolas Keller ◽  
Olivier Reiff ◽  
Valérie Keller ◽  
Marc J. Ledoux
Keyword(s):  
Shape Memory ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Synthesis Method ◽  
Sic Particles ◽  
Memory Synthesis

scholarly journals Inter-connected and open pore hierarchical TS-1 with controlled framework titanium for catalytic cyclohexene epoxidation

2018 ◽  
Vol 8 (8) ◽  
pp. 2211-2217 ◽  
Author(s):  
Yilai Jiao ◽  
Abdul-Lateef Adedigba ◽  
Qian He ◽  
Peter Miedziak ◽  
Gemma Brett ◽  
...  
Keyword(s):  
Synthesis Method ◽  
Cyclohexene Epoxidation ◽  
Post Synthesis

A post-synthesis method was developed to reduce the extra-framework titanium in TS-1 zeolites in which TPAOH was used to convert amorphous Ti to zeolitic phases.

Sign in / Sign up

Export Citation Format

Share Document