Thermal Hydrogen Reduction for Synthesis of Gold Nanoparticles in the Nanochannels of Mesoporous Silica Composite

2014 ◽  
Vol 70 (1) ◽  
Author(s):  
Mohamad Azani Jalani ◽  
Leny Yuliati ◽  
Hendrik O. Lintang
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Mesoporous Silica ◽  
Hydrogen Reduction ◽  
Sol Gel ◽  
Average Particle Size ◽  
Average Particle ◽  
Silica Composite ◽  
Interpore Distance ◽  
New Strategy

Gold nanoparticles (AuNPs) with small particle size have been difficult to be synthesized due to their strong agglomeration. Herein we report that the nanochannels of mesoporous silica synthesized from template sol-gel synthesis were utilized to prepare AuNPs by employing thermal hydrogen reduction. Mesoporous silica composite with an interpore distance of 4.1 nm was successfully fabricated as a thin film by an amphiphilic trinuclear gold(I) pyrazolate complex ([Au3Pz3]C10TEG) as a template. In contrast to calcination method of this composite and the bulk [Au3Pz3]C10TEG complex at 450ºC for 3 h, thermal hydrogen reduction at 250ºC for 2 h showed transmission electron microscope (TEM) images and diffraction pattern with smaller particle size (14.5 nm) and more homogenous distribution of AuNPs with up to 44% of the particle size in the range of 10 to 20 nm. The decreasing of average particle size in this new strategy indicated by the red-shifting of the surface plasmon resonance (SPR) band from 518 (AuNPs from the bulk [Au3Pz3]C10TEG complex) and 544 (calcination) to 558 nm.

Synthesis of Mesoporous Silica Nanocomposites for Preparation of Gold Nanoparticles

2014 ◽  
Vol 925 ◽  
pp. 233-237 ◽  
Author(s):  
Mohamad Azani Jalani ◽  
Leny Yuliati ◽  
Salasiah Endud ◽  
Hendrik Oktendy Lintang
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Mesoporous Silica ◽  
Sol Gel ◽  
Average Particle Size ◽  
Silica Film ◽  
Cubic Phase ◽  
Average Particle ◽  
Interpore Distance ◽  
Sol Gel Synthesis

Gold nanoparticles (AuNPs) having particle size less than 10 nm can exhibit enhancement of surface area to give high activity such as in catalytic reaction. However, it is hard to synthesize AuNPs with small particle size due to the strong agglomeration. Herein we report that channels of mesoporous silica synthesized via the template sol-gel synthesis can be used to prepare AuNPs by calcination method. Mesoporous silica with an interpore distance of 4.1 nm was successfully fabricated as transparent thin film by using an amphiphilic trinuclear gold (I) pyrazolate complex as a template for the sol-gel synthesis. Upon calcination at 450 °C for 3 h, silica film nanocomposites showed red-shifting of surface plasmon resonance (SPR) bands from 518 (AuNPs from the bulk) to 544 nm owing to decreasing of the average particle size. The formation of AuNPs was also supported by the appearance of diffraction peaks of d111 at 2θ = 38.20° having a cubic phase. Moreover, transmission electron microscope (TEM) images and X-ray diffraction (XRD) peaks also showed smaller and more homogenous distribution of AuNPs.

Synthesis and Characterization of Water-Soluble Monolayer-Protected Gold Nanoparticles

2011 ◽  
Vol 415-417 ◽  
pp. 617-620 ◽  
Author(s):  
Yan Su ◽  
Ying Yun Lin ◽  
Yu Li Fu ◽  
Fan Qian ◽  
Xiu Pei Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Transmission Electron

Water-soluble gold nanoparticles (AuNPs) were prepared using 2-mercapto-4-methyl-5- thiazoleacetic acid (MMTA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The AuNPs product was analyzed by transmission electron microscopy (TEM), UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). The TEM image shows that the particles were well-dispersed and their average particle size is about 5 nm. The UV-vis absorption and FTIR spectra confirm that the MMTA-AuNPs was stabilized by the carboxylate ions present on the surface of the AuNPs.

Preparation of Magnesium-Based Cobalt-Ferrites (Co1−xMgxFe2O4) Nanoparticles by Sol–Gel Auto Combustion Method

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760012
Author(s):  
S. Gowreesan ◽  
A. Ruban Kumar
Keyword(s):  
Particle Size ◽  
Structural Parameters ◽  
Sol Gel ◽  
Average Particle Size ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Powder Xrd ◽  
Average Particle ◽  
Cobalt Ferrites ◽  
Auto Combustion

The scope of the present work is in enhancing the particle size, and dielectric properties of Mg-substituted Cobalt ferrites nanoparticles prepared by sol–gel auto combustion method. The different ratios of Mg-substituted Co Ferrites (Co[Formula: see text]MgxFe2O4([Formula: see text], 0.05, 0.10, 0.15, 0.20 and 0.30)) are calcinated at 850[Formula: see text]C. The synthesized nanoparticles were characterized by powder XRD, FTIR, FE-SEM, EDX techniques and dielectric behavior. The structural parameters were confirmed from powder XRD and the average particle size is obtained from 39 to 67 nm due to the substitution of Mg[Formula: see text] which was calculated by Debye Scherrer’s formula. FE-SEM showed the surface morphology of the different ratio of the sample. The dielectric loss has measured the frequency range of 50[Formula: see text]Hz–5[Formula: see text]MHz. From electrical modulus, conductivity relaxation and thermal activation of charge carriers has been discussed.

Fabrication and Microstructure of ZnO-TiO2 Composite Membranes by a Reverse Micelle and Sol-Gel Processing

2006 ◽  
Vol 510-511 ◽  
pp. 786-789 ◽  
Author(s):  
Dong Sik Bae ◽  
Byung Ik Kim ◽  
Kyong Sop Han
Keyword(s):  
Particle Size ◽  
Reverse Micelle ◽  
Porous Alumina ◽  
Sol Gel ◽  
Average Particle Size ◽  
Composite Membranes ◽  
Dip Coating ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Alumina Support

ZnO-TiO2 nanoparticles were synthesized by a reverse micelle and sol-gel process. The average particle size of the colloid was below 30 nm and well dispersed in the solution. ZnOTiO2 composite membranes were fabricated by using the dip-coating method on a porous alumina support. ZnO-TiO2 composite membranes showed a crack-free microstructure and narrow particle size distribution even after the heat treatment up to 600°C. The average particle size of the membrane was 30-40nm, and the pore size of ZnO-TiO2 composite membrane was below 10 nm.

Facile Synthesis and Characterization of Fe-Co Nanoparticles Supported Silica Rice Husk

2016 ◽  
Vol 709 ◽  
pp. 66-69
Author(s):  
Jeyashelly Andas ◽  
Rahmah Atikah Rosdi ◽  
Nur Izzati Mohd Anuar
Keyword(s):  
Particle Size ◽  
Rice Husk ◽  
Sol Gel ◽  
Average Particle Size ◽  
Average Particle ◽  
Silica Source ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Bimetallic Materials ◽  
Co Nanoparticles

A series of Fe-Co nanoparticles were synthesized via sol-gel route at acidic, neutral and basic condition using rice husk as the silica source. The synthesized nanomaterials were designated as Fe-Co3, Fe-Co7 and Fe-Co9 and characterized by Fourier Transform Infrared (FTIR), Transmission Electron Microscope (TEM) and particle size analyzer. The great effect of pH was clearly evidenced from the shifting in the siloxane bond in the FTIR spectrum. TEM investigation confirmed the existence of discrete and almost sphere like nanoparticles. The particle size decreased with an increase in the pH, registering the smallest average particle size at pH 9. In brief, this study promises a fast, rapid and promising method for the conversion of silica rice husk into nanoscale bimetallic materials.

Preparation and Characterization of Gold Nanoparticles in the Presence of Citrate and Soybean Seed Extract in an Acidic Conditions

Drug Research ◽  
2017 ◽  
Vol 67 (05) ◽  
pp. 266-270 ◽  
Author(s):  
Ebrahim Izadi ◽  
Ali Rasooli ◽  
Abolfazl Akbarzadeh ◽  
Soodabeh Davaran
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Size Distribution ◽  
Average Particle Size ◽  
Soybean Seed ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Soybean Extract ◽  
Average Size

AbstractThrough the present study, an eco-friendly method was used to synthesize the gold nanoparticles (GNPs) by using the sodium citrate and extract of the soybean seed as reducing the agents at PH 3. X-Ray diffraction (XRD) method was used to evaluate the crystal structure of as-synthesized NPs and it’s revealed that this method leads to well crystallized GNPs. In order to determine the particle size and their distribution, field emission scanning microscopy (FE-SEM) and dynamic light scattering (DLS) were used. The results showed that, the average particle size distribution of synthesized GNPs in solutions containing of the soybean extract and 1% citrate at PH 3 is about 109.6 and 140.9 nm, respectively. Also, we find that the average size of GNPs is 40 and 33 nm from solutions of citrate and soybean extract, respectively. It was concluded that using the extract of soybean seeds as reducing agent can lead to GNPs with small size and narrow size distribution.

scholarly journals Application of surfactants for the synthesis of qualitative hydroxide and metallic cobalt nanopowders

2021 ◽  
pp. 4-11
Author(s):  
Van Minh Nguyen ◽  
Tien Hiep Nguyen ◽  
Stanislav V. Gorobinsky
Keyword(s):  
Particle Size ◽  
Hydrogen Reduction ◽  
Cetylpyridinium Chloride ◽  
Average Particle Size ◽  
Sodium Dodecyl ◽  
Chemical Precipitation ◽  
Spherical Particles ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Application Of Surfactants

In this work, nanopowders (NP) Co(OH)2 were obtained by chemical precipitation from aqueous solutions of cobalt nitrate Co(NO3)2 and alkali NaOH (10 wt. %) using surfactants: sodium dodecyl sulfate (SDS) and cetylpyridinium chloride (CPC) (0.1 wt. %). It was shown that Co(OH)2 NP with 0.1% SDS is the best quality product, since its dispersion increases more than 2 times compared to the samples with 0.1% CPC and without surfactants. In this case, the Co(OH)2 NP has the form of flakes with an irregular shape and a nanometer size (about 100 nm) with an average thickness of 30 nm. It was found that the average particle size of Co NP obtained by hydrogen reduction of Co(OH)2 NP with 0.1% SDS at 280°C has a maximum on the distribution histogram shifted to the interval 41–50 nm, which is characterized by a narrow particle size distribution and represents spherical particles sintered with each other.

Sol-Gel Silica Particles for Controlled Release Applications

2004 ◽  
Vol 847 ◽  
Author(s):  
Christophe Barbé ◽  
Sandrine Calleja ◽  
Linggen Kong ◽  
Elizabeth Drabarek ◽  
Alexandra Bush ◽  
...  
Keyword(s):  
Particle Size ◽  
Controlled Release ◽  
Release Rate ◽  
Sol Gel ◽  
Average Particle Size ◽  
Silica Particles ◽  
Average Particle ◽  
Independent Control ◽  
Ceramic Particles ◽  
Innovative Method

ABSTRACTUsing sol-gel technology combined with water-in-oil (W/O) emulsions, we have developed an innovative method for producing ceramic particles with independent control over the release rate and particle size. The average particle size can be varied from 10 nm to 100 μm and is controlled by the emulsion chemistry. The release rate can be independently varied from mg/hours to mg/month, and is controlled by the internal microstructure of the particles and the initial sol-gel chemistry.

Preparation and Characterization of Macromeritic Tungsten Powder Reduced by Ammonium Paratungstate at Medium Temperature

2012 ◽  
Vol 468-471 ◽  
pp. 2584-2587
Author(s):  
Rui Xin Wang ◽  
Zhi Meng Guo ◽  
Jun Jie Hao ◽  
Ji Luo ◽  
Yan Jun Xin
Keyword(s):  
Particle Size ◽  
Hydrogen Reduction ◽  
Tungsten Powder ◽  
Average Particle Size ◽  
Raw Material ◽  
Metal Salts ◽  
Average Particle ◽  
Medium Temperature ◽  
Ammonium Paratungstate ◽  
Ammonium Tungstate

The macromeritic tungsten powder was prepared by wet hydrogen reduction at medium temperature; the coarse powder of Ammonium paratungstate powder (APT) was used as raw material. It is obtained by evaporating and crystallizating adding alkalia metal salts in the solution of ammonium tungstate. The microstructure, phase composition and particle size of the macromeritic tungsten powder were investigated by SEM, XRD and test analysis sieves. The effects of kinds, contents of alkali metal salts and the temperature in the reduction were studied. The results revealed that ideal tungsten powder, with the good fluditity, spherical, integrate and well-distributed, could be obtained. The raw material is the solution of ammonium tungstate adding NaCl, Li2CO3 and KCl , the concentration of them are all 3g/L, and it is under the condition of 1000°C,180min in wet hydrogen atmosphere. The average particle size is 67μm, the maximum is 150μm, the biggest loose density is 13.41g/cm3, and the best powder flowability is 9s/50g.

Effects of Preparation Conditions on Characters of Hydrophobic Silica Granular Aerogel and its Applications

2012 ◽  
Vol 600 ◽  
pp. 190-193 ◽  
Author(s):  
Wei Wei ◽  
Jing Yi Zhang ◽  
Li Ping Wu ◽  
Guo Tong Qin
Keyword(s):  
Particle Size ◽  
Ambient Pressure ◽  
High Surface ◽  
Sol Gel ◽  
Average Particle Size ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Ambient Pressure Drying ◽  
Average Particle ◽  
Hydrophobic Silica

The hydrophobic silica granular aerogels were synthesized via sol-gel synthesis followed by ambient pressure drying. The tetraethyloxylane (TEOS) was used as original precursor. The aerogels were analyzed using nitrogen adsorption, scanning electron microscopy (SEM) and laser particle size analyzer. It was found that the aerogel was mesoporous material with high surface area. The aerogels were prepared in grain form by dipping into disperse solution in order to adsorption application. The average particle size of the aerogel was controlled by pH and disperse solution volume. The pH also affected gel time. The aerogels were used to absorb phenol from water. The saturated adsorption amount could reach up to 145 mg•g-1.

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