Effects of Mixed Template on Pore Structure of Order of Crack-Free Monolithic Mesoporous Carbon

2014 ◽  
Vol 926-930 ◽  
pp. 85-88
Author(s):  
Jian Jiao ◽  
Yong Hong Cui ◽  
Yu Cai ◽  
Pan Pan Lv
Keyword(s):  
Pore Size ◽  
Mesoporous Carbon ◽  
Triblock Copolymer ◽  
Pore Diameter ◽  
Nitrogen Adsorption ◽  
Molar Ratio ◽  
Element Analysis ◽  
Resorcinol Formaldehyde ◽  
Transmission Electron ◽  
Mixed Template

Crack-free monolithic mesoporous carbon with worm-like structure has been synthesized by low-temperature autoclaving that use triblock copolymer F127 or P123 as composite template, and resorcinol-formaldehyde resol as carbon precursor. The effects of the composite template ratio on the structure of mesoporous carbon were studied by transmission electron microscopy, nitrogen adsorption measurements and element analysis. The results indicated that mesoporous carbon are worm-like structure when use F127/P123 as composite template. Compared mesoporous carbon synthesized by a single template, the pore size distribution of the mesoporous carbon synthesized by the composite template are directly affected by the molar ratio of P123 in the composite templates, however, the pore size is significantly enlarged when using F127/P123 as template. The pore size of mesoporous carbon increased to 12.0nm when the molar ratio of P123 in the composite templates is 67%. We achieved adjustable pore diameter by use F127/P123 changing the molar ratio of P123 in the composite templates.

Fabrication of Carbon Aerogels

2006 ◽  
Vol 11-12 ◽  
pp. 19-22 ◽  
Author(s):  
Y.N. Feng ◽  
Lei Miao ◽  
Yong Ge Cao ◽  
T. Nishi ◽  
Sakae Tanemura ◽  
...  
Keyword(s):  
Pore Size ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Limited Range ◽  
Molar Ratio ◽  
Carbon Aerogels ◽  
Resorcinol Formaldehyde ◽  
Catalyst Content ◽  
Fabrication Parameters ◽  
Pyrolysis Processes

RF (Resorcinol-Formaldehyde) aerogels and carbon aerogels were prepared through the sol-gel method following the routes of polymerization, gelation, supercritical drying and pyrolysis processes. The influence of fabrication parameters on the textural structure of the samples, e.g., specific surface area, pore size, and pore size distribution, etc., were systematically investigated. With a decrease in the R/F molar ratio, or an increase in the catalyst content within a limited range, the porosity of the nanostructure materials increases. The optimal temperature of pyrolysis for RF aerogel was investigated by TGA (Thermogravimetric Analysis).

scholarly journals Synthesis and characterization of porous silica and polyaniline-porous silica composite materials with high surface area

2014 ◽  
Vol 49 (1) ◽  
pp. 1-8
Author(s):  
US Akhtar ◽  
MK Hossain ◽  
MS Miran ◽  
MYA Mollah
Keyword(s):  
Electron Microscopy ◽  
Pore Size ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Porous Silica ◽  
Nitrogen Adsorption ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Cylindrical Pore

Porous silica materials were synthesized from tetraethyl orthosilicate (TEOS) using Pluronic P123 (non-ionic triblock copolymer, EO20PO70O20) as template under acidic conditions which was then used to prepare polyaniline (PAni) and porous silica composites (PAnisilica) at a fixed molar ratio. These materials were characterized by nitrogen adsorption-desorption isotherm measured by Barrett-Joyner- Halenda (BJH) method and pore size distribution from desorption branch and surface area measured by the Brunauer-Emmett-Teller (BET) method, scanning electron microscopy (SEM), transmission electron microscopy (TEM), TEM-energy dispersive X-ray (EDX) and Fourier transform infrared (FT-IR) spectroscopy. The composite maintains its structure even after the polymerization and the polymer is dispersed on the inorganic matrix. The rod-like porous silica was about 1?m to 1.5 ?m long and on an average the diameter was in the range of 300- 500 nm. The SEM and TEM images show well ordered 2d hexagonal pore, high specific surface area (850 m2g-1) and uniform pore size of ca. 6.5 nm in diameter. After incorporation of PAni inside the silica pore, framework of porous silica did not collapse and the surface area of the composite was as high as 434 m2g-1 which was 5.5 time higher than our previous report of 78.3 m2g-1. Due to shrinkage of the framework during the incorporation of aniline inside the silica, the pore diameter slightly increase to 7.5 nm but still showing Type IV isotherm and typical hysteresis loop H1 implying a uniform cylindrical pore geometry. DOI: http://dx.doi.org/10.3329/bjsir.v49i1.18847 Bangladesh J. Sci. Ind. Res. 49(1), 1-8, 2014

Positron Annihilation Study of Porous ZnO Synthesized with Soft Template

2017 ◽  
Vol 373 ◽  
pp. 299-302
Author(s):  
Bo Zhou ◽  
Chong Yang Li ◽  
Ning Qi ◽  
Zhi Quan Chen
Keyword(s):  
Pore Size ◽  
Positron Lifetime ◽  
Nitrogen Adsorption ◽  
Soft Template ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Long Lifetime ◽  
Positron Annihilation Study ◽  
Adsorption Desorption

Porous ZnO were synthesized with soft template method using zinc acetate Zn (CH3COO)2·2H2O as precursor and block copolymer F127 as the surfactant. Nitrogen adsorption-desorption measurements indicate that the ZnO sample contains large pores with mean diameter of about 30 nm. However, both small-angle X-ray diffraction and transmission electron microscope measurements indicate that the pore ordering is missing. Positron lifetime measurements reveal two long lifetime components in the porous ZnO. The longest lifetime τ4 (75 ns) corresponds to ortho-positronium (o-Ps) annihilation in large pores. The pore size estimated from τ4 is about 10.6 nm. This is much smaller than that estimated from Nitrogen adsorption-desorption measurements. In addition, the intensity I4 is only about 2.2%. This is probably due to the chemical quenching and/or inhibition of positronium formation induced by ZnO, which reduces o-Ps lifetime and intensity, and leads to under estimation of the pore size.

scholarly journals SYNTHESIS AND ELECTROCHEMICAL PROPERTIES OF MESOPOROUS CARBON SUPPORTED WELL–DISPERSED COBALT OXIDES NANOPARTICLES

2018 ◽  
Vol 55 (1B) ◽  
pp. 230
Author(s):  
Nguyen Van Tu
Keyword(s):  
Electron Microscopy ◽  
Cobalt Oxide ◽  
Mesoporous Carbon ◽  
Good Control ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Oxide Nanoparticles ◽  
Cobalt Oxide Nanoparticles ◽  
Transmission Electron ◽  
Adsorption Desorption

In this article, well–dispersed cobalt oxide nanoparticles supported on mesoporous carbon (CMK–3) have been successfully synthesized. The composites were characterized by field emission scanning electron microscopy, transmission electron microscopy, X–ray diffraction and nitrogen adsorption–desorption analysis. The results have confirmed that, at a cobalt loading of 15 wt%, the composites have not only retained mesoporous structure of the support but also shown a good control of dispersed cobalt oxide nanoparticles with size of ~4 nm. The electrochemical property tests for the synthesized samples have shown significant improvement compared to the blank carbon (CMK–3) without cobalt oxide incorporation.

scholarly journals Supramolecular Reinforcement of a Large Pore 2D Covalent Organic Framework

2021 ◽  
Author(s):  
Shashini Diwakara ◽  
Whitney Ong ◽  
Yalini Wijesundara ◽  
Robert Gearhart ◽  
Fabian Herbert ◽  
...  
Keyword(s):  
Pore Size ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Nitrogen Adsorption ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Structural Reinforcement ◽  
Transmission Electron ◽  
Covalently Linked ◽  
Green Fluorescent

Two dimensional covalent organic frameworks (2D-COFs) are a class of crystalline porous organic polymers that consist of covalently linked, two dimensional sheets that can stack together through non-covalent interactions. Here we report the synthesis of a novel COF, called PyCOFamide, which has an experimentally observed pore size that is greater than 6 nm in diameter. This is among the largest pore size reported to date for a 2D-COF. PyCOFamide exhibits permanent porosity and high crystallinity as evidenced by the nitrogen adsorption, powder X-ray diffraction, and high-resolution transmission electron microscopy. We show that the pore size of PyCOFamide is large enough to accommodate fluorescent proteins such as Superfolder green fluorescent protein and mNeonGreen. This work demonstrates the utility of non-covalent structural reinforcement in 2D-COFs to produce larger, persistent pore sizes than previously possible.

Synthesis and Characterization of Mesoporous Carbon with MoO3 Loading via Ultrasonic Assembly

2010 ◽  
Vol 654-656 ◽  
pp. 2277-2280
Author(s):  
Xi Long ◽  
Wen Chen ◽  
Shao Jiang Chen ◽  
Chun Xia Zhao
Keyword(s):  
Electron Microscopy ◽  
Mesoporous Carbon ◽  
Nitrogen Adsorption ◽  
Photoelectron Spectra ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Precursor

Mesoporous carbon with MoO3 loading (MoO3/CMK-3) was obtained via ultrasonic assembly with CMK-3 as the host material and MoO3 as the guest material which was yield from MoO3ּpH2O2ּqH2O sol precursor. The microstructures of such MoO3/CMK-3 composites were characterized by X-ray diffraction (XRD), nitrogen adsorption and desorption, X-ray photoelectron spectra (XPS), Fourier-transform infrared (FTIR) and transmission electron microscopy (TEM). The results show that the method of ultrasonic assembly was efficient to highly disperse MoO3 nanoparticales into the channels of mesoporous carbon.

Size-Controllable Synthesis of Worm-Like SiO2 Microspheres Using Dodecylamine as Direct Agent in Ethanol/Water Solvent System

2013 ◽  
Vol 448-453 ◽  
pp. 154-159
Author(s):  
Xue Ling Zhang ◽  
Wei Yao Zhu ◽  
Meng Jing Cao ◽  
Qiang Cai ◽  
Xiao Feng Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Nitrogen Adsorption ◽  
Solvent System ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Controllable Synthesis ◽  
Silica Microspheres ◽  
X Ray ◽  
Water Solvent ◽  
Transmission Electron

Size-controllable synthesis of worm-like microporous monodispersed SiO2microspheres using dodecylamine (DDA) as direct agent in ethanol-water solvent system was firstly developed by varying the proportion of reactants. The products were characterized with scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), small angle X-ray diffraction (SAXRD) and nitrogen adsorption. The results showed that the SiO2microspheres with size of 50nm~1um could be prepared by varying the molar ratio of water/ethanol when the molar ratio of (DDA)/tetraethyl orthosilicate (TEOS) is 0.4 and the concentration of TEOS varied from 0.138 to 0.248mol/L. This method is simple and convenient, the prepared SiO2microspheres are monodispersed and uniform, the worm-like pore size is about 1.4nm. The size controllable silica microspheres could be used as an excellent additional medium to alter rheological behavior of fluid after surface modification..

Enhanced Capacitance of Microwave-assisted Functionalized Ordered Mesopourous Carbon for Supercapacitors

2012 ◽  
Vol 15 (3) ◽  
pp. 203-209 ◽  
Author(s):  
B. Portales-Martínez ◽  
R.G. González-Huerta ◽  
J.M. Domínguez-Esquivel ◽  
C.A. Cortés-Escobedo
Keyword(s):  
Photoelectron Spectroscopy ◽  
Mesoporous Carbon ◽  
Nitrogen Adsorption ◽  
Electrochemical Capacitance ◽  
X Ray ◽  
Molding Method ◽  
Microwave Assisted ◽  
Transmission Electron ◽  
Ordered Mesoporous ◽  
Adsorption Desorption

The electrochemical capacitance for a double layer of ordered mesoporous carbon (OMC) nanofibers functionalized under differing conditions is presented. OMC nanofibers were prepared using the molding method from SBA-15 and sucrose. Functionalisation was performed using varying HNO3 concentrations at 110°C and 120°C assisted by microwave radiation over 3 minutes. The transmission electron micrographs of the resulting fibers are reported. The capacitance, surface area and functional groups as functions of the acidity and heat treatment were analysed via cyclic voltammetry, nitrogen adsorption-desorption, and X-ray photoelectron spectroscopy, respectively. Ordered nanofibers treated with 7.7 M HNO3 at 110°C exhibited the highest capacitance.

scholarly journals The Role of Cations in Resorcinol–Formaldehyde Gel Textural Characteristics

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 60
Author(s):  
Stewart J. Taylor ◽  
Liu Yang ◽  
Ashleigh J. Fletcher
Keyword(s):  
Pore Size ◽  
Pore Diameter ◽  
Textural Properties ◽  
Average Pore ◽  
Salting Out ◽  
Resorcinol Formaldehyde ◽  
Catalyst Composition ◽  
Solids Content ◽  
Insight Into

The production of resorcinol–formaldehyde xerogels has yielded insight into the gelation processes underpinning their structures. In this work, the role of the cation species from the catalyst is probed by studying the simultaneous addition of sodium carbonate and calcium carbonate to a resorcinol–formaldehyde mixture. Twenty-eight xerogels were prepared by varying the solids content, catalyst concentration, and catalyst composition, and each was analysed for its textural properties, including the surface area and average pore diameter. The results indicate that the role of the cation is linked to the stabilisation of the clusters formed within the system, and that the Group II catalyst causes the salting out of the oligomers, resulting in fewer, larger clusters, hence, an increase in pore size and a broadening of the pore size distribution. The results provide insight into how these systems can be further controlled to create tailored porous materials for a range of applications.

scholarly journals Infuence of Microstructure in Drug Release Behavior of Silica Nanocapsules

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Gema Gonzalez ◽  
Amaya Sagarzazu ◽  
Tamara Zoltan
Keyword(s):  
Pore Size ◽  
Drug Loading ◽  
Morphological Characteristics ◽  
Nitrogen Adsorption ◽  
Release Process ◽  
Al Content ◽  
Surface Areas ◽  
Transmission Electron ◽  
Good Potential ◽  
Model Drug

Meso- and nanoporous structures are adequate matrices for controlled drug delivery systems, due to their large surface areas and to their bioactive and biocompatibility properties. Mesoporous materials of type SBA-15, synthesized under different pH conditions, and zeolite beta were studied in order to compare the different intrinsic morphological characteristics as pore size, pore connectivity, and pore geometry on the drug loading and release process. These materials were characterized by X-ray diffraction, nitrogen adsorption, scanning and transmission electron microscopy, and calorimetric measurements. Ibuprofen (IBU) was chosen as a model drug for the formulation of controlled-release dosage forms; it was impregnated into these two types of materials by a soaking procedure during different periods. Drug loading and release studies were followed by UV-Vis spectrophotometry. All nano- and mesostructured materials showed a similar loading behavior. It was found that the pore size and Al content strongly influenced the release process. These results suggest that the framework structure and architecture affect the drug adsorption and release properties of these materials. Both materials offer a good potential for a controlled delivery system of ibuprofen.

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