A Novel Structural Mesoporous Alumina/Yttrium Doped Zirconia Nanocrystalline Composite Derived by Solvothermal Approach

2005 ◽  
Vol 20 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Hangrong Chen ◽  
Xin Michael Wang ◽  
Jianlin Shia ◽  
Ping Xiao ◽  
Dongsheng Yan
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Mesoporous Alumina ◽  
Infrared Transmission ◽  
Scanning Calorimetry ◽  
Uniform Size ◽  
Transmission Electron ◽  
Nanocrystalline Zirconia ◽  
Nanocrystalline Composite

A novel structural mesoporous alumina (40 mol%)/yttrium doped zirconia nanocrystalline composite has been synthesized by a solvothermal process using ethanol and ethylene glycol as a co-solvent. X-ray diffraction, thermogravimetry/differential scanning calorimetry, Fourier transform infrared, transmission electron microscopy, and nitrogen adsorption are used for the structural characterization. This novel mesoporous alumina/zirconia nanocomposite presents nanocrystalline zirconia particles with a uniform size less than 5 nm surrounded by alumina, forming a kind of core-shell structure after calcined at 800 °C. The mesostructural composite has high surface area (higher than 250 m2/g) and a narrow pore-size distribution of about 3.2 nm throughout the composite sample. The uniformly distributed nanocrystalline zirconia particles and the surrounding wormlike alumina framework act as the inorganic wall for the mesopores.

Sucrose-Template Synthesis of Mesoporous Alumina from Aqueous Systems

2010 ◽  
Vol 6 (2) ◽  
Author(s):  
Benjing Xu ◽  
Zifeng Yan ◽  
Yuxia Zhu ◽  
Huiping Tian ◽  
Jun Long
Keyword(s):  
Thermal Analyses ◽  
High Surface ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Aqueous System ◽  
Mesoporous Alumina ◽  
X Ray Diffraction ◽  
Excellent Thermal Stability ◽  
Transmission Electron ◽  
Adsorption Desorption

Mesoporous alumina was prepared by using sucrose as a structure-directing template in an aqueous system. The resultant samples were characterized by using different methods such as x-ray diffraction, transmission electron microscopy, nitrogen adsorption-desorption analysis, and thermogravimetric and differential thermal analyses. The results showed that the prepared mesoporous gamma alumina has high surface area, uniform pore size distribution and excellent thermal stability.

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

Synthesis and Characterization of ZrO2/Graphene Nanocomposite Materials

2012 ◽  
Vol 531 ◽  
pp. 161-164 ◽  
Author(s):  
Zong Hua Wang ◽  
Fu Qiang Zhu ◽  
Jan Fei Xia ◽  
Fei Fei Zhang ◽  
Yan Zhi Xia ◽  
...  
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Transmission Electron ◽  
Ft Ir ◽  
Graphene Nanocomposite ◽  
Adsorption Desorption

Zirconia/graphene (ZrO2/graphene) nanocomposite has been successfully synthesized by a simple method. The as-prepared nanocomposite was characterized using transmission electron microscopy (TEM), FT-IR spectroscopy, power X-ray diffraction (XRD) and nitrogen adsorption-desorption. It was found that tetragonal ZrO2was uniformly deposited on graphene, which resulted in the formation of two-dimensional nanocomposite, it showed a high surface area of 165 m2/g.

SYNTHESIS AND CHARGE–DISCHARGE PROPERTIES OF POROUS CO3O4 NANOROD BUNDLE ELECTRODE

NANO ◽  
2012 ◽  
Vol 07 (05) ◽  
pp. 1250036 ◽  
Author(s):  
FEI TENG ◽  
JUN WANG ◽  
MINDONG CHEN ◽  
DENNIS DESHENG MNEG
Keyword(s):  
Electron Microscopy ◽  
High Surface ◽  
High Surface Area ◽  
Lithium Ion ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
Transmission Electron ◽  
Rate Capacity ◽  
Nanorod Bundle ◽  
Charge Discharge

The Co3O4 nanorod bundles are synthesized by a hydrothermal method. The samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED), X-ray powder diffractometer (XRD), and nitrogen adsorption. It is important that the as-obtained Co3O4 nanorod bundles are assembled by nanoparticles. The porous nanorod bundle electrode exhibits a higher rate capacity and a higher reverse capability for lithium ion battery than the solid nanorods, which is attributed to the high surface area and the porous structure.

scholarly journals Pd Nanoparticles Stabilized on the Cross-Linked Melamine-Based SBA-15 as a Catalyst for the Mizoroki–Heck Reaction

2021 ◽  
Author(s):  
Ayat Nuri ◽  
Abolfazl Bezaatpour ◽  
Mandana Amiri ◽  
Nemanja Vucetic ◽  
Jyri-Pekka Mikkola ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
High Surface ◽  
High Surface Area ◽  
Coupling Reaction ◽  
Pd Nanoparticles ◽  
Significant Activity ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Ft Ir

AbstractMesoporous SBA-15 silicate with a high surface area was prepared by a hydrothermal method, successively modified by organic melamine ligands and then used for deposition of Pd nanoparticles onto it. The synthesized materials were characterized with infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen physisorption, scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP-OES). The catalyst was effectively used in the Mizoroki–Heck coupling reaction of various reactants in the presence of an organic base giving the desired products in a short reaction time and with small catalysts loadings. The reaction parameters such as the base type, amounts of catalyst, solvents, and the temperature were optimized. The catalyst was easily recovered and reused at least seven times without significant activity losses. Graphic Abstract

High Cr(VI) Adsorption Performance of Coal-Based Activated Carbon in Aqueous Solution

2013 ◽  
Vol 798-799 ◽  
pp. 1123-1127
Author(s):  
Hua Lei Zhou ◽  
Qiong Qiong Zhu ◽  
Dong Hua Huang
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Pore Structure ◽  
Ph Value ◽  
High Surface ◽  
High Surface Area ◽  
Koh Activation ◽  
Transmission Electron ◽  
Mesoporous Adsorbent ◽  
Initial Ph

The activated carbon with high surface area was prepared by KOH activation from anthracite and used as adsorbent for removal of Cr (VI) from aqueous solution. The pore structure and surface properties were characterized by N2 adsorption at 77K, transmission electron microscope (TEM) and Fourier transform infrared spectroscopy ( FTIR). Effect of pH and isotherms at different temperature were investigated. Results show that the prepared carbon is a microporous-and mesoporous-adsorbent with developed pore structure and abundant surface oxygen-containing groups. PH value of the solution plays key function on the adsorption. The chemical adsorption dominates the adsorption process. The activated carbon exhibits much higher Cr adsorption capacity than the commercial activated carbon at initial pH of ~3. The equilibrium adsorption data are fitted by both Freundlich model and Langmuir model well.

scholarly journals Electrospun Multiple-Chamber Nanostructure and Its Potential Self-Healing Applications

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2413 ◽  
Author(s):  
Yubo Liu ◽  
Xinkuan Liu ◽  
Ping Liu ◽  
Xiaohong Chen ◽  
Deng-Guang Yu
Keyword(s):  
Electron Microscope ◽  
Electrochemical Corrosion ◽  
Average Diameter ◽  
Self Healing ◽  
Scanning Calorimetry ◽  
Uniform Size ◽  
Transmission Electron ◽  
Reactive Fluids ◽  
Amine Curing ◽  
First Time

To address the life span of materials in the process of daily use, new types of structural nanofibers, fabricated by multifluid electrospinning to encapsulate both epoxy resin and amine curing agent, were embedded into an epoxy matrix to provide it with self-healing ability. The nanofibers, which have a polyacrylonitrile sheath holding two separate cores, had an average diameter of 300 ± 140 nm with a uniform size distribution. The prepared fibers had a linear morphology with a clear three-chamber inner structure, as verified by scanning electron microscope and transmission electron microscope images. The two core sections were composed of epoxy and amine curing agents, respectively, as demonstrated under the synergistic characterization of Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry. The TGA results disclosed that the core-shell nanofibers contained 9.06% triethylenetetramine and 20.71% cured epoxy. In the electrochemical corrosion experiment, self-healing coatings exhibited an effective anti-corrosion effect, unlike the composite without nanofibers. This complex nanostructure was proven to be an effective nanoreactor, which is useful to encapsulate reactive fluids. This engineering process by multiple-fluid electrospinning is the first time to prove that this special multiple-chamber structure has great potential in the field of self-healing.

Nanostructured Pt/WOx-C Solids as Electrocatalyst for PEMFC

2012 ◽  
Vol 15 (3) ◽  
pp. 165-170 ◽  
Author(s):  
M.L. Hernández-Pichardo ◽  
R.G. González-Huerta ◽  
P. Del Angel ◽  
E. Palacios-González ◽  
S.P. Paredes-Carrera
Keyword(s):  
Proton Exchange Membrane ◽  
High Surface ◽  
High Surface Area ◽  
Proton Exchange ◽  
Synthesis Methods ◽  
Co Tolerance ◽  
Transmission Electron ◽  
Anode Electrocatalysts ◽  
Exchange Membrane ◽  
Nanostructured Pt

Platinum nanoparticles supported on high surface area carbon black (e.g., Vulcan XC-72) are the most commonly used catalysts for both cathode and anode in proton exchange membrane fuel cells (PEMFCs), however, some other catalysts such as Pt/MoOx and Pt/WOx are also considered promising, due to their higher activity, stability and enhanced CO tolerance. This work is focused on the synthesis and characterization of nanostructured Pt/WOx-C as both cathode and anode electrocatalysts for PEMFCs. The Pt deposit on the surface of the support is a crucial step in the synthesis of the catalytic materials. Because of this, different synthesis methods were probed in order to find the conditions for the higher dispersion and accessibility of Platinum over the WOx-C support and to improve the PEMFC cathode stability. The catalysts were prepared by UV and ultrasound assisted approaches, and characterized by Transmission Electron Microscopy as well as lineal and cyclic voltammetry.

Magnetic Fe3O4@C nanoparticles as adsorbents for removal of amoxicillin from aqueous solution

2013 ◽  
Vol 69 (1) ◽  
pp. 147-155 ◽  
Author(s):  
Babak Kakavandi ◽  
Ali Esrafili ◽  
Anoushiravan Mohseni-Bandpi ◽  
Ahmad Jonidi Jafari ◽  
Roshanak Rezaei Kalantary
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Kinetic Models ◽  
High Surface ◽  
High Surface Area ◽  
Order Kinetic ◽  
Magnetic Composites ◽  
Factors Affecting ◽  
Transmission Electron ◽  
Pseudo Second Order

In the present study, powder activated carbon (PAC) combined with Fe3O4 magnetite nanoparticles (MNPs) were used for the preparation of magnetic composites (MNPs-PAC), which was used as an adsorbent for amoxicillin (AMX) removal. The properties of magnetic activated carbon were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Brunaeur, Emmett and Teller and vibrating sample magnetometer. The operational factors affecting adsorption such as pH, contact time, adsorbent dosage, initial AMX concentration and temperature were studied in detail. The high surface area and saturation magnetization for the synthesized adsorbent were found to be 671.2 m2/g and 6.94 emu/g, respectively. The equilibrium time of the adsorption process was 90 min. Studies of adsorption equilibrium and kinetic models revealed that the adsorption of AMX onto MNPs-PAC followed Freundlich and Langmuir isotherms and pseudo-second-order kinetic models. The calculated values of the thermodynamic parameters, such as ΔG°, ΔH° and ΔS° demonstrated that the AMX adsorption was endothermic and spontaneous in nature. It could be concluded that MNPs-PAC have a great potential for antibiotic removal from aquatic media.

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

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