scholarly journals Synthesis of SAPO-34 Using Different Combinations of Organic Structure-Directing Agents

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Tuan Doan ◽  
Khang Nguyen ◽  
Phong Dam ◽  
Thanh Huyen Vuong ◽  
Minh Thang Le ◽  
...  
Keyword(s):  
Surface Area ◽  
Crystal Size ◽  
High Surface ◽  
High Surface Area ◽  
Physicochemical Characteristics ◽  
29Si Nmr ◽  
Organic Structure ◽  
Tetraethylammonium Hydroxide ◽  
Volume Measurements ◽  
Structure Directing Agents

The effects of different mixtures of organic structure-directing agents (OSDAs) on the formation of SAPO-34 structure have been investigated. Different OSDAs, namely, triethylamine (TEA), tetraethylammonium hydroxide (TEAOH), and morpholine (Mor) and their combinations were used to synthesize SAPO-34 by a hydrothermal method. The template concentration was optimized by eliminating the competing phases to obtain the purest form of SAPO-34 phase. The as-synthesized samples were analyzed by XRD, FE-SEM/EDS, FT-IR, surface area/pore volume measurements, NH3-TPD, TG/DTA, and 29Si NMR MAS. The selection of template notably impacts the crystal size and physicochemical characteristics of as-synthesized SAPO-34. The sample prepared with 3 Mor : 3 TEA : 1 TEAOH exhibited the highest total acidity, smallest crystal size below 3 µm, and high surface area up to 697 m2/g.

scholarly journals SYNTHESIS OF THE ZSM-5 ZEOLITE WITH MIXTURES BINARY OF TETRAETHYLAMMONIUM HYDROXIDE AND AMINES AS ORGANIC STRUCTURE DIRECTING AGENTS

2020 ◽  
Vol 6 (3) ◽  
pp. 0200-0206
Author(s):  
Diogo Pimentel de Sá da Silva ◽  
Bruno José Barros da Silva ◽  
Antonio Osimar Sousa da Silva
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Reaction System ◽  
Nitrogen Adsorption ◽  
Organic Structure ◽  
Tetraethylammonium Hydroxide ◽  
Fine Chemistry ◽  
Structure Directing Agents ◽  
Materials Used ◽  
Adsorption Desorption

Among the microporous materials used in heterogeneous catalysis, zeolites have become promising due to the relevant physicochemical and catalytic properties. Noteworthy is the zeolite ZSM-5 used as a catalyst in reactions in the areas of petrochemical and fine chemistry, such as cracking, isomerization, alkylation and aromatization reactions of olefins.  In view of this, the objective of this work was to synthesize the ZSM-5 zeolite, through binary mixtures of tetraethylammonium hydroxide (TEAOH) and different amines (n-butylamine, isobutylamine and diisobutylamine) acting as organic structure directing agents (SDA's). X-ray diffractometry indicated that only the reaction system containing TEAOH and n-butylamine provided the achievement of highly crystalline ZSM-5 and without competing phases. The nitrogen adsorption-desorption isotherms indicated that a material with a high surface area (329 m2·g-1) and pore volume (0.26 cm3·g-1) was obtained. Thus, it was possible to identify a new synthesis route in obtaining the ZSM-5 zeolite.

Effect of Sericin Protein on Growth of Hydroxyapatite over Surface of Silk Fibers Using Simulated Body Fluid

2012 ◽  
Vol 622-623 ◽  
pp. 1764-1767
Author(s):  
Onanong Sukjai ◽  
Piyapong Asanithi ◽  
Pichet Limsuwan ◽  
Supanee Limsuwan
Keyword(s):  
Simulated Body Fluid ◽  
Surface Area ◽  
Body Fluid ◽  
Crystal Size ◽  
High Surface ◽  
High Surface Area ◽  
Research Topic ◽  
Silk Fibers ◽  
Nucleation Barrier ◽  
New Research

Crystal of hydroxyapatite (HAp) was grown on silk fibers using simulated body fluid (SBF) at a temperature of 37 °C. Effect of SBF concentrations and sericin protein on the growth of HAp crystals on the silk fiber was discussed. The results showed that sericin protein was an important parameter to induce HAp crystals. Furthermore, the crystal was grown perfectly for both 1.0 and 1.5  standard SBF concentrations but difference in HAp crystal size. Sericin protein may lower nucleation barrier and high surface area to absorb SBF for HAp nucleation. These results may be a new research topic on HAp crystallization using protein as a seed. It may lead to further improvement and applied for many HAp-based biomaterial applications.

Photocatalytic Degradation of Acetaldehyde by Sol-Gel TiO2 Nanoparticles: Effect of the Physicochemical Properties on the Photocatalytic Activity

2011 ◽  
Vol 691 ◽  
pp. 92-98 ◽  
Author(s):  
R. Carrera ◽  
A.L. Vázquez ◽  
S. Castillo ◽  
E.M. Arce Estrada
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Photocatalytic Oxidation ◽  
Crystal Size ◽  
Uv Light ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Synthesis Method

Nowadays, nanostructured semiconductor materials offer promising opportunities for a new generation of materials such as TiO2nanoparticles with improved properties for their application in the environmental catalysis field. It is well known that the phocatalytic activity of the TiO2nanoparticles is strongly dependent on the surface area, crystal size, phase composition and synthesis method. Thus, the preparation conditions clearly affect the photocatalytic activity of the TiO2nanoparticles. This work deals with the study of the structure of TiO2nanoparticles that were synthesized by the sol-gel method (using isopropanol as solvent), and calcined at 200 and 500°C. The obtained samples were characterized by the XRD-Rietveld refinement, BET and TEM techniques; and tested in the photodecomposition of acetaldehyde. The evaluations were carried out at room temperature by using CH3CHO (300 ppmv), O2(2.0 %) in helium balance in a quartz glass photoreactor (gas phase) with a 365-UV light lamp. According to the results, the sample that presented the highest activity in the photocatalytic oxidation of acetaldehyde (96.4%) was the one annealed at 200 °C. This sample showed the following proportion of phases: anatase (62.88%) with a tetragonal structure (a=0.3790926, b=0.3790926, c=0.9495732) nm; and b) brookite (37.12%) with an orthorhombic structure (a=0.9167624, b=0.5416461, c=0.5210546) nm. The surface area was 189 m2/g and the average crystal size was 7.03 nm. From the results, it can be seen that this material showed high activity in the photocatalytic degradation of acetaldehyde because of: the presence of a mixture of the anatase (higher proportion) and brookite phases, nanometric crystal size and high surface area obtained in this TiO2material. According to the aforementioned, this material can be considered as a good option for the decomposition of acetaldehyde and other volatile organic compounds (VOCs) in confined spaces.

scholarly journals Porous intermetallic Ni2XAl (X = Ti or Zr) nanoparticles prepared from oxide precursors

2021 ◽  
Vol 3 (7) ◽  
pp. 1901-1905
Author(s):  
Yasukazu Kobayashi ◽  
Shohei Tada ◽  
Ryuji Kikuchi
Keyword(s):  
Chemical Synthesis ◽  
Surface Area ◽  
Crystal Size ◽  
High Surface ◽  
High Surface Area ◽  
Small Crystal ◽  
Small Crystal Size

Chemical synthesis of porous intermetallic Ni2XAl (X = Ti or Zr) nanoparticles with small crystal size (24–34 nm) and high surface area (10–71 m2 g−1).

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

scholarly journals Rugae-like FeP nanocrystal assembly on a carbon cloth: an exceptionally efficient and stable cathode for hydrogen evolution

Nanoscale ◽  
2015 ◽  
Vol 7 (25) ◽  
pp. 10974-10981 ◽  
Author(s):  
Xiulin Yang ◽  
Ang-Yu Lu ◽  
Yihan Zhu ◽  
Shixiong Min ◽  
Mohamed Nejib Hedhili ◽  
...  
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Hydrogen Evolution ◽  
Hydrogen Generation ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Efficiency ◽  
Carbon Cloth ◽  
Nanocrystal Assembly

High surface area FeP nanosheets on a carbon cloth were prepared by gas phase phosphidation of electroplated FeOOH, which exhibit exceptionally high catalytic efficiency and stability for hydrogen generation.

High Surface Area NiCoP Nanostructure as Efficient Water Splitting Electrocatalyst for the Oxygen Evolution Reaction

2021 ◽  
pp. 111312
Author(s):  
Sisir Maity ◽  
Dheeraj Kumar Singh ◽  
Divya Bhutani ◽  
Suchitra Prasad ◽  
Umesh V. Waghmare ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Surface ◽  
High Surface Area

scholarly journals Fast synthesis of high surface area bio-based porous carbons for p-nitrophenol removal

MethodsX ◽  
2021 ◽  
pp. 101464
Author(s):  
Yichen Wu ◽  
Nan Zhang ◽  
Charles-François de Lannoy
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Porous Carbons ◽  
Fast Synthesis

Synthesis of high surface area and functionalized nanoporous biocarbons and their efficiency for CO2 capture and supercapacitors

2021 ◽  
Author(s):  
Gurwinder Singh ◽  
Rohan Bahadur ◽  
Ajanya Maria Ruban ◽  
Jefrin Marykala Davidraj ◽  
Dawei Su ◽  
...  
Keyword(s):  
Energy Storage ◽  
Surface Area ◽  
Co2 Capture ◽  
Water Purification ◽  
High Surface ◽  
High Surface Area ◽  
Energy Storage And Conversion ◽  
Waste Biomass ◽  
Fabrication Technology ◽  
Significant Attention

Nanoporous biocarbons derived from waste biomass have created significant attention owing to their great potential for energy storage and conversion and water purification. However, the fabrication technology for these materials...

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