Kinetic Barriers and Microscopic Mechanisms of Noble Gas Adsorption by Nanoporous γ‐Mg(BH4)2 Obtained by means of Sub‐Second X‐Ray Diffraction

2020 ◽  
Author(s):  
Iurii Dovgaliuk ◽  
Irena Senkovska ◽  
Xiao Li ◽  
Vadim Dyadkin ◽  
Yaroslav Filinchuk ◽  
...  
Keyword(s):  
Gas Adsorption ◽  
Noble Gas ◽  
X Ray Diffraction ◽  
X Ray ◽  
Kinetic Barriers

Hydrothermal Treatment of Coprecipitated YSZ Powders

2010 ◽  
Vol 660-661 ◽  
pp. 983-988 ◽  
Author(s):  
Alexander Rodrigo Arakaki ◽  
Walter Kenji Yoshito ◽  
Valter Ussui ◽  
Dolores Ribeiro Ricci Lazar
Keyword(s):  
Surface Area ◽  
Hydrothermal Treatment ◽  
Gas Adsorption ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
Immersion Method ◽  
Cubic Symmetry ◽  
X Ray ◽  
Granulometric Analysis ◽  
Symmetry Surface

Zirconia stabilized with 8.5 mol% yttria (YSZ) were synthesized by coprecipitation and resulting gels were hydrothermallly treated at 200°C and 220 PSI for 4, 8 and 16 hours. Products were oven dried at 70°C for 24 hours, isostatically pressed as pellets and sintered at 1500 °C for 1 hour. Powders were characterized for surface area with N2 gas adsorption, X-ray diffraction, laser diffraction granulometric analysis and scanning and transmission electronic microscopy. Density of ceramics was measured by an immersion method based on the Archimedes principle. Results showed that powders dried at 70°C are amorphous and after treatment has tetragonal/cubic symmetry. Surface area of powders presented a significant reduction after hydrothermal treatment. Ceramics prepared from hydrothermally treated powders have higher green density but sintered pellets are less dense when compared to that made with powders calcined at 800°C for 1 hour due to the agglomerate state of powders. Solvothermal treatment is a promising procedure to enhance density.

Preparation of CuS/SiO2 Composite Modified Aerogel and Its Superoleophobic and Photocatalytic Properties

NANO ◽  
2020 ◽  
Vol 15 (02) ◽  
pp. 2050017
Author(s):  
Ke-Cheng Yang ◽  
Li-Hui Xu ◽  
Hong Pan ◽  
Li-Ming Wang ◽  
Yong Shen ◽  
...  
Keyword(s):  
Gas Adsorption ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Photocatalytic Properties ◽  
X Ray Diffraction ◽  
Sliding Angle ◽  
Nitrogen Gas ◽  
Ir Spectrometry ◽  
X Ray ◽  
Ft Ir

In this study, CuS/SiO2 composite modified aerogel was prepared by the incorporation of hollow spherical CuS into methyltrimethoxysilane-based SiO2 sol and modification with hexadecafluorodecyltriethoxysilane via acid-base catalyzed sol–gel reaction and drying under ambient pressure. The CuS/SiO2 composite modified aerogel was characterized by Fourier-transform infrared (FT-IR) spectrometry, scanning electron microscope (SEM), nitrogen gas adsorption and desorption and X-ray diffraction (XRD), respectively. The effects of CuS and fluorosilane concentration on density and porosity of aerogel, oleophobic and photocatalytic properties were evaluated. The results showed that structure and physical properties of aerogel had some effect by introducing CuS and fluorosilane, and the CuS/SiO2 composite modified aerogel with density of 0.146[Formula: see text]g/cm3 and specific surface area of 241[Formula: see text]m2/g achieved super-oleophobicity with oil contact angle of 152.8∘ and sliding angle of 10∘, and good photocatalytic properties for methylene blue.

scholarly journals Copper-Containing Films Obtained by the Simple Citrate Sol–Gel Route for NO2 Detection: Adsorption and Kinetic Study

Chemosensors ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 79
Author(s):  
Tatiana N. Myasoedova ◽  
Nina K. Plugotarenko ◽  
Tatiana A. Moiseeva
Keyword(s):  
Annealing Temperature ◽  
Gas Adsorption ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
X Ray ◽  
Percolation Effect ◽  
Kinetics Of ◽  
Gas Effect ◽  
No2 Detection

The citrate sol–gel method was utilized for the fabrication of copper-containing films sensitive to NO2 gas. Effect of annealing temperature on the film phase composition, morphology, and sensor response was studied. X-ray diffraction reveals the formation of Cu2Cl(OH)3 phase at 250 °C and the CuO phase at 350 and 500 °C. It was found out that the films annealed at 250 °C and 350 °C showed the best sensor characteristics. The influence of thermal degradation on the probability of percolation effect in films and its connection to a decrease of gas sensitivity was studied. The kinetics of the NO2 gas adsorption on the film’s surface was described following the Elovich model. Activation energy estimated from the ln(S) vs. 1/T plots was 252 and 30 kJ/mol for the films annealed at 250 and 350 °C, respectively.

A series of thermal stable lanthanide porphyrins with a condensed three-dimensional porous open framework: Gas adsorption and magnetic properties

2015 ◽  
Vol 19 (09) ◽  
pp. 1072-1079 ◽  
Author(s):  
Xiu-Guang Yi ◽  
Jian-Gen Huang ◽  
Rong-Hua Hu ◽  
Zhi-Gang Luo ◽  
Yun-Peng Pei ◽  
...  
Keyword(s):  
Gas Adsorption ◽  
Magnetic Measurements ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Open Framework ◽  
Paramagnetic Behavior ◽  
Adsorption Measurement ◽  
Ft Ir ◽  
Thermal Stable

A series of lanthanide porphyrins, [ LnIII(TPPSIV) ]n·n H 5 O 2 ( Ln = La , Sm , Eu ; H2TPPS = tetra(4-sulfonatophenyl)porphyrin), have been synthesized through solvothermal reactions and structurally characterized by single-crystal X-ray diffraction. These compounds are characterized by a condensed three-dimensional (3-D) porous open framework. Magnetic measurements reveal that these compounds show ferromagnetic, antiferromagnetic and paramagnetic behavior, respectively. All of the compounds exhibit highly thermal stability. The FT-IR and adsorption measurement of CO 2 were also studied.

scholarly journals Efficiency of TiO2 catalyst supported by modified waste fly ash during photodegradation of RR45 dye

2019 ◽  
Vol 26 (1) ◽  
pp. 292-300 ◽  
Author(s):  
Vanja Gilja ◽  
Zvonimir Katančić ◽  
Ljerka Kratofil Krehula ◽  
Vilko Mandić ◽  
Zlata Hrnjak-Murgić
Keyword(s):  
Fly Ash ◽  
Gas Adsorption ◽  
Sol Gel ◽  
Efficiency Evaluation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Synthesis ◽  
Adsorption Desorption

AbstractThe waste fly ash (FA) material was subjected to chemical treatment with HCl at elevated temperature for a different time to modify its porosity. Modified FA particles with highest surface area and pore volume were further used as a support for TiO2 catalyst during FA/TiO2 nanocomposite preparation. The nanocomposite photocatalysts were obtained by in situ sol–gel synthesis of titanium dioxide in the presence of FA particles. To perform accurate characterization of modified FA and FA/TiO2 nanocomposite photocatalysts, gas adsorption-desorption analysis, X-ray diffraction, scanning electron microscopy, UV/Vis and Infrared spectroscopy were used. Efficiency evaluation of the synthesized FA/TiO2 nanocomposites was performed by following the removal of Reactive Red 45 (RR45) azo dye during photocatalytic treatment under the UV-A irradiation. Photocatalysis has been carried out up to five cycles with the same catalysts to investigate their stability and the possible reuse. The FA/TiO2 photocatalyst showed very good photocatalytic activity and stability even after the fifth cycles. The obtained results show that successfully modified waste fly ash can be used as very good TiO2 support.

Synthesis and Characterization of Nanocrystalline CeO2

2006 ◽  
Vol 306-308 ◽  
pp. 1103-1108
Author(s):  
Abdul Hadi ◽  
Iskandar Idris Yaacob
Keyword(s):  
Fine Particles ◽  
Gas Adsorption ◽  
Mesoporous Structure ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Face Centered ◽  
Adsorption Desorption

Nanocrystalline CeO2 has been synthesized at room temperature using water-in-oil (w/o) microemulsion technique. The structure and properties of the nanocrystalline CeO2 were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and gas adsorption desorption measurement. XRD results showed the synthesized CeO2 has a face centered cubic structure with crystallite size of about 5.2 nm. TEM observation also indicated the presence of nanometer sized particles of CeO2. Coarser particles were also observed due to agglomeration. Gas adsorption desorption isotherms showed the behavior of fine particles with mesoporous structure.

Mechanochemical Synthesis of Nanocrystalline CeO2: The Effect of Annealing Temperatures on the Particle Size

2006 ◽  
Vol 517 ◽  
pp. 252-256 ◽  
Author(s):  
Abdul Hadi ◽  
Iskandar Idris Yaacob ◽  
Lee Seok Ling
Keyword(s):  
Annealing Temperature ◽  
Gas Adsorption ◽  
Weight Ratio ◽  
X Ray Diffraction ◽  
Treatment Results ◽  
Scanning Calorimetry ◽  
Characterization Methods ◽  
X Ray ◽  
Annealing Temperatures ◽  
Adsorption Desorption

Cerium dioxide (CeO2) nanoparticles were synthesized by a novel mechanochemical process. The precursors of Ce2(CO3)3.xH2O and NaOH were mixed at a weight ratio of 4 to 1. The mixtures were milled using a planetary ball mill with ball to powder ratio of 10:1. The products were then characterized using a battery of characterization methods, including X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and gas adsorption-desorption measurement. The as-prepared particles were largely amorphous with an average specific surface area of about 119.94 m2/g. Nanocrystalline CeO2 with crystallite size of 4.5 nm was obtained when the sample was annealed in air at 350 oC. The heat treatment results showed that the crystallinity of nanocrystalline CeO2 increased with increasing annealing temperature.

scholarly journals An Ecofriendly Synthesis of 2-oxazolidinone From 2-aminoethanol and Urea Under Solvent-free Condition Using CeO2 Nanoparticles

2021 ◽  
Author(s):  
ALI NEMATI KHARAT ◽  
Mehrnaz Aliahmadi
Keyword(s):  
Gas Adsorption ◽  
Sol Gel ◽  
Solvent Free ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
X Ray ◽  
Solvent Free Condition ◽  
Solvent Free Conditions ◽  
Adsorption Desorption ◽  
Desorption Method

Abstract Cerium dioxide nanoparticles were prepared by the sol-gel method using cellulose as a template and used in the synthesis of 2-oxazolidinone from urea and 2-aminoethanol under solvent-free conditions. All the reaction parameters were optimized to obtain the best selectivity and conversion. The selectivity of 100 % to 2-oxazolidinone with a pretty complete conversion of about 98.4 % was achieved. The prepared catalyst was characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and volumetric isothermal nitrogen gas adsorption-desorption method (BET).

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