Preparation and Characterization of AuNP/Al2O3 with Bimodal Nanoporous Structure

2008 ◽  
Vol 135 ◽  
pp. 53-56
Author(s):  
Young Hun Kim ◽  
Ji Bong Joo ◽  
Woo Young Kim ◽  
Jeong Jin Lee ◽  
Jong Heop Yi
Keyword(s):  
Particle Size ◽  
Metal Particle ◽  
High Surface ◽  
High Surface Area ◽  
High Reactivity ◽  
Nanoporous Structure ◽  
Metal Particle Size ◽  
Novel Method ◽  
Al2o3 Catalyst

AuNP (gold nanoparticle) supported by oxide shows a high reactivity for a PROX (preferential oxiation) reaction at low temperature. Au catalysts were usually prepared by conventional methods such as precipitation, impregnation and vapor phase grafting. In this study, we developed a novel method for the preparation of AuNPs supported on a bimodal nanoporous alumina. The AuNPs were prepared in a toluene phase by the modified Brust method. The metal particle size was able to be controlled from 2 to 50 nm via the control of the surfactant concentrations. The resulting materials were characterized by BET, FE-SEM, TEM, and XRD analyses. After calcinations at 700oC, AuNP/Al2O3 catalyst revealed a bimodal nanoporous structure, with the pore sizes of 3.5 and 7 nm, and demonstrated both a high surface area (350 m2/g) and pore volume (0.9 cm3/g).

Synthesis and Characterization of Nanocrystalline Hydroxyapatite Powder

2015 ◽  
Vol 1087 ◽  
pp. 142-146 ◽  
Author(s):  
Rosli Asmawi ◽  
Mohd Halim Irwan Ibrahim ◽  
Azriszul Mohd Amin ◽  
Najwa Mustapha ◽  
Iis Sopyan
Keyword(s):  
Particle Size ◽  
Calcium Phosphate ◽  
High Surface ◽  
High Surface Area ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Nanocrystalline Hydroxyapatite

Nanocrystalline hydroxyapatite (HA) powder was synthesized by a simple heating process involving simple chemical reaction. The characterization of the produced powder showed that the powder is nanosize with particle in the range of 30-70 mm in diameter and almost evenly spherical in shape. The powder also has a high surface area of 43.16 m2/g. Field Emission Scanning Electron Microscopy (FESEM) observation showed the crystallite and particle size become bigger with an increment of calcination temperature, indicating increasing of crystallinity.. FESEM observation showed the particle size become bigger with an increment of calcinations temperature. It is in agreement with the crystallite size analysis, obtained by Scherer’s formula and particle size analysis, measured by nanoSizer. X-ray Diffraction (XRD) and Fourier Transform Infra Red Spectroscopy (FTIR) analyses exhibited the same result, where HA phase was clearly observed at at various temperatures up to 600 ̊C. However, at temperature more than 600 ̊C, Tri calcium phosphate (TCP) phase appeared suppressing the HA phase, producing biphasic calcium phosphate.

Manufacturing and characterization of ZnO and ZnO-doped frit crystal by physical and optical methods

2019 ◽  
Vol 33 (21) ◽  
pp. 1950233 ◽  
Author(s):  
Osama Khodrog ◽  
Norlaili Kabir ◽  
Xue Gong ◽  
Qinghai Yuan ◽  
Jianhua Liu
Keyword(s):  
Particle Size ◽  
Energy Gap ◽  
High Surface ◽  
High Surface Area ◽  
Optical Methods ◽  
Raman Shift ◽  
Interaction Field ◽  
Characterization Studies ◽  
Zno Powder

This study was carried out to determine the physical and optical properties of zinc oxide (ZnO) and ZnO-doped Frit. Two groups of ZnO were prepared, namely, pure ZnO and ZnO-doped Frit. ZnO was prepared as ZnO disc and ZnO powder, and its high surface area and other characterized physical properties were expected to be the figure of merit in increasing the radiation interaction. Field emission scanning electron microscope and energy-dispersive X-ray (EDX) (FESEM) were utilized for analysis purposes. The particle size of pure ZnO was larger than ZnO-doped Frit in which ZnO-doped Frit particle size ranged in the scope of 260 nm, while pure ZnO was in the scope of 300 nm. The bond of the ZnO-doped Frit was better compared to pure ZnO. Raman spectroscopy characterization studies showed that the tops for both spectra displayed the same Raman shift. More top in ZnO-doped Frit was seen due to its bigger amount of impurities in the crystal. The energy gap for discs by UV of P338 was 3.37 eV, while the energy gap for ZnO-doped Frit was 3.26 eV. This study yielded impressive results in terms of the manufacture of ZnO, whereby the energy gap was proved by Ultraviolet–visible (UVV) device. In contrast, the ZnO-doped Frit generated inadequate result due to the small percentage used.

Novel Method for Fast Characterization of High-Surface-Area Electrocatalytic Materials Using a Carbon Fiber Microelectrode

2010 ◽  
Vol 114 (6) ◽  
pp. 2640-2644 ◽  
Author(s):  
D. Strmcnik ◽  
Nejc Hodnik ◽  
S. B. Hocevar ◽  
D. van der Vliet ◽  
M. Zorko ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Fiber Microelectrode ◽  
Novel Method

Control of Ni metal particle size in Ni/SiO2 catalysts by calcination and reduction temperatures

1987 ◽  
Vol 83 (10) ◽  
pp. 3189 ◽  
Author(s):  
Hiroyuki Tamagawa ◽  
Kyuichi Oyama ◽  
Tsuyoshi Yamaguchi ◽  
Hiroshige Tanaka ◽  
Hideyasu Tsuiki ◽  
...  
Keyword(s):  
Particle Size ◽  
Metal Particle ◽  
Metal Particle Size

Iron Nanoparticle Production by the Method of Electric Explosion of Wire

2021 ◽  
Vol 13 ◽  
Author(s):  
Elena Gryaznova ◽  
Alexey Pustovalov
Keyword(s):  
Particle Size ◽  
Specific Energy ◽  
Initial Conditions ◽  
High Surface ◽  
High Surface Area ◽  
Electrical Explosion ◽  
Narrow Particle Size Distribution ◽  
Magnetic Characteristics ◽  
Specific Energy Input ◽  
Iron Wire

Background: The widespread use of the iron nanopowders connected with widely range of characteristics such as size, magnetic characteristics and high surface area and that is why in the literature are present many researches of its different applications. Objective: The work studies the influence of the conditions of the iron wire electrical explosion on the course of the explosion process and the dispersed composition of the resulting metal nanopoweder. Method: Experiments on electrical explosion of iron wires were carried out in the laboratory setup with the different initial conditions of electrical explosion of the iron wire. Results: The influence of the initial wire electrical explosion conditions on the explosion regime, the specific energy input into the conductor, and the specific energy released in the arc stage of discharge are definitely determined. The empirical equations for calculation of the initial wire electrical explosion conditions for providing the critical explosion in the argon medium at a pressure of 2·105 Pa were defined. It has been established that for synthesis of iron nanopowders with a narrow particle size distribution, it is preferable to use modes with a high level of the energy released in the arc stage of the discharge. Conclusion: It was found that disabling the arc stage of the discharge during EEW leads to the decreasing of the average surface particle size by 50%.

scholarly journals USE OF MONTMORILLONITE CLAY FOR ADSORPTION MALACHITE GREEN DYE

2019 ◽  
Vol 16 (32) ◽  
pp. 279-286
Author(s):  
Marcos Antônio KLUNK ◽  
Zeban SHAH ◽  
Paulo Roberto WANDER
Keyword(s):  
Malachite Green ◽  
Retention Time ◽  
High Surface ◽  
High Surface Area ◽  
Exchange Capacity ◽  
Montmorillonite Clay ◽  
Malachite Green Dye ◽  
Low Levels ◽  
High Concentrations

Removal of malachite green dye by adsorption from aqueous solution using montmorillonite clay is reported in this work. A malachite green dye is a cationic widely used in textile industries. Due to its persistence in the aquatic environment, it becomes a problem for aquatic and terrestrial organisms. This dye can be adsorbed through various techniques, but high acquisition and operating costs preclude widespread use. Several adsorbents are available in the market, but the most outstanding are the clays, especially the montmorillonites. These clays are finely divided material ( 0.002 mm), and its adsorption properties are continuously investigated. Types of clays 2:1 (two tetrahedral to one octahedral) are called expandables. The montmorillonite has a potential for dyes removal in wastewater due to the high surface area, porosity with excellent cation exchange capacity conferring its adsorbent property. This work aims to use the montmorillonite as an adsorption system in stages to textile decolorization effluent, composed of malachite green dye, reproduced in the laboratory. The characterization of the clay gives high purity and is used as adsorbent of good quality and efficiency. The retention of dyes in the system composed of montmorillonite arranged in separation stages was efficient. The effect of dye concentration and retention time are the most important parameters used in this study. High concentrations and retention time below 24 hours resulted in low levels of removal (25%). On the other hand, the low level of initial concentration increases removal efficiency (57%). Thus, the results obtained in this work allow concluding that montmorillonite is able to removal malachite green dye.

scholarly journals Preparation and characterization of activated carbons from albizia saman pod

2017 ◽  
Vol 36 (3) ◽  
pp. 44-53
Author(s):  
G. D. Akpen ◽  
M. I. Aho ◽  
N. Baba
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Activated Carbons ◽  
High Surface ◽  
High Surface Area ◽  
Volatile Matter ◽  
Sieve Analysis ◽  
Albizia Saman ◽  
Temperature Surface

Activated carbon was prepared from the pods of Albizia saman for the purpose of converting the waste to wealth. The pods were thoroughly washed with water to remove any dirt, air- dried and cut into sizes of 2-4 cm. The prepared pods were then carbonised in a muffle furnace at temperatures of 4000C, 5000C, 6000C ,7000C and 8000C for 30 minutes. The same procedure was repeated for 60, 90, 120 and 150 minutes respectively. Activation was done using impregnationratios of 1:12, 1:6, 1:4, 1:3, and 1:2 respectively of ZnCl2 to carbonised Albizia saman pods by weight. The activated carbon was then dried in an oven at 1050C before crushing for sieve analysis. The following properties of the produced Albizia saman pod activated carbon (ASPAC) were determined: bulk density, carbon yield, surface area and ash, volatile matter and moisture contents. The highest surface area of 1479.29 m2/g was obtained at the optimum impregnation ratio, carbonization time and temperature of 1:6, 60 minutes and 5000C respectively. It was recommended that activated carbon should be prepared from Albizia saman pod with high potential for adsorption of pollutants given the high surface area obtained.Keywords: Albizia saman pod, activated carbon, carbonization, temperature, surface area

scholarly journals Diatoms - nature materials with great potential for bioapplications

2016 ◽  
Vol 70 (6) ◽  
pp. 613-627 ◽  
Author(s):  
Djordje Medarevic ◽  
Dusan Losic ◽  
Svetlana Ibric
Keyword(s):  
Drug Delivery ◽  
Gas Sensing ◽  
High Surface ◽  
High Surface Area ◽  
Raw Material ◽  
Nanoporous Structure ◽  
Mechanical Resistance ◽  
Diatom Frustule ◽  
Wide Availability ◽  
Made In

Diatoms are widespread unicellular photosynthetic algae that produce unique highly ordered siliceous cell wall, called frustule. Micro- to nanoporous structure with high surface area that can be easily modified, high mechanical resistance, unique optical features (light focusing and luminescence) and biocompatibility make diatom frustule as a suitable raw material for the development of devices such as bio- and gas sensors, microfluidic particle sorting devices, supercapacitors, batteries, solar cells, electroluminescent devices and drug delivery systems. Their wide availability in the form of fossil remains (diatomite or diatomaceous earth) as well as easy cultivation in the artificial conditions further supports use of diatoms in many different fields of application. This review focused on the recent achievements in the diatom bioapplications such as drug delivery, biomolecules immobilization, bio- and gas sensing, since great progress was made in this field over the last several years.

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