Relations Between Structure and Texture in Nano-Sized Aluminas

1994 ◽  
Vol 351 ◽  
Author(s):  
Dominique J. Coster ◽  
Pierre Levitz ◽  
Jose J. Fripiat
Keyword(s):  
Heat Treatment ◽  
Aluminum Content ◽  
High Surface ◽  
Aqueous Media ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Degree Of Condensation ◽  
High Surface Area Materials

ABSTRACTAlumina xerogels were prepared by a two step hydrolysis in non-aqueous media. This synthesis produced high surface area materials with controlled amount of pentacoordinated aluminum. The effect of heat treatment and of the preparation procedure on the physical characteristics of the powder was determined by nitrogen adsorption and X-Ray diffraction, whereas the aluminum coordination was studied by 27Al MAS NMR. The pore size distribution and the pentahedral aluminum content (up to 700°C) are closely related to the degree of condensation of the prehydrolysed oligomer species.

scholarly journals Attached β-cyclodextrin/γ-(2,3-epoxypropoxy) propyl trimethoxysilane to graphene oxide and its application in copper removal

2017 ◽  
Vol 75 (10) ◽  
pp. 2403-2411 ◽  
Author(s):  
Zongxue Yu ◽  
Qi Chen ◽  
Liang Lv ◽  
Yang Pan ◽  
Guangyong Zeng ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Esterification Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cavity Structure ◽  
Optimum Ph ◽  
Exchange Adsorption ◽  
Langmuir Isotherm Model

The environmental applications of graphene oxide and β-cyclodextrin (β-CD) have attracted great attention since their first discovery. Novel nanocomposites were successfully prepared by using an esterification reaction between β-cyclodextrin/γ-(2,3-epoxypropoxy) propyl trimethoxysilane grafted graphene oxide (β-CD/GPTMS/GO). The β-CD/GPTMS/GO nanocomposites were used to remove the Cu2+ from aqueous solutions. The characteristics of β-CD/GPTMS/GO were detected by scanning electron microscopy (SEM), Fourier transform infrared, X-ray diffraction (XRD), thermogravimetric analysis (TG) and energy dispersive X-ray (EDX). The dispersibility of graphene oxide was excellent due to the addition of β-CD. The adsorption isotherms data obtained at the optimum pH 7 were fitted by Langmuir isotherm model. The excellent adsorption properties of β-CD/GPTMS/GO for Cu2+ ions could be attributed to the apolar cavity structure of β-CD, the high surface area and abundant functional groups on the surface of GO. The adsorption patterns of β-CD/GPTMS/GO were electrostatic attraction, formation of host-guest inclusion complexes and the ion exchange adsorption. The efficient adsorption of β-CD/GPTMS/GO for Cu2+ ions suggested that these novel nanocomposites may be ideal candidates for removing other cation pollutants from waste water.

scholarly journals Promoting Li/MgO Catalyst with Molybdenum Oxide for Oxidative Conversion of n-Hexane

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 354 ◽  
Author(s):  
Cassia Boyadjian ◽  
Leon Lefferts
Keyword(s):  
Raman Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Deep Oxidation ◽  
Oxidative Conversion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anionic Species ◽  
Dehydrogenation Reactions ◽  
Lithium Molybdate

In this work, molybdena-promoted Li/MgO is studied as a catalyst for the oxidative conversion of n-hexane. The structure of the catalysts is investigated with X-ray Diffraction (XRD) and Raman spectroscopy. The MoO3/Li/MgO catalyst contains three types of molybdena-containing species, the presence of which depend on molybdena loading. At low Mo/Li ratios (i) isolated dispersed [MoO4]2− anionic species are observed. At high Mo/Li ratios, the formation of crystalline lithium molybdate phases such as (ii) monomeric Li2MoO4 and tentatively (iii) polymeric Li2Mo4O13 are concluded. The presence of these lithium molybdates diminishes the formation of Li2CO3 in the catalyst. Subsequently, the catalyst maintains high surface area and stability with time-on-stream during oxidative conversion. Molybdena loading as low as 0.5 wt % is sufficient to induce these improvements, maintaining the non-redox characteristics of the catalyst, whereas higher loadings enhance deep oxidation and oxidative dehydrogenation reactions. Promoting a Li/MgO catalyst with 0.5 wt % MoO3 is thus efficient for selective conversion of n-hexane to alkenes, giving alkene yield up to 24% as well as good stability.

Ni-doped, urchin-like Bi2S3 particles for electrocatalytic oxidation of glucose

2021 ◽  
pp. 2150006
Author(s):  
Biao Wang ◽  
Ya Liu ◽  
Xu Huai ◽  
Yuqing Miao
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Electrocatalytic Oxidation ◽  
High Surface ◽  
High Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Capacitance Current ◽  
Oxidation Of Glucose

In order to develop non-noble metal-based electrocatalysts for glucose oxidation, the Ni-doped, urchin-like Bi2S3 particles were prepared by a solvothermal method using the solvent of ethylene glycol/H2O. The obtained products were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The background signal from capacitance current is relatively low and the electrocatalytic oxidation current of glucose relatively high due to the urchin-like nanostructure of Bi2S3 particles and high surface area where the presence of Bi also improves the electrocatalytic performance of NiII/NiIII shift.

Synthesis and Analysis of High Surface Area Vanadium Carbide Nanoparticles

2012 ◽  
Vol 585 ◽  
pp. 95-99 ◽  
Author(s):  
M. Mahajan ◽  
K. Singh ◽  
O.P. Pandey
Keyword(s):  
Surface Area ◽  
Vanadium Carbide ◽  
High Surface ◽  
High Surface Area ◽  
X Ray Diffraction ◽  
High Melting Point ◽  
X Ray ◽  
Transmission Electron ◽  
Product Powder ◽  
Scanning Electron

Vanadium carbide is known for its applications due to extreme hardness and high melting point. In this present work, vanadium carbide nanoparticles have been synthesized in a specially designed stainless steel autoclave by solvothermal route using vanadium pentoxide (V2O5) as precursor along with a hydrocarbon acetone (C3H6O) in the presence of reducing agent magnesium (Mg). The optimization of reaction time was studied at constant temperature of 800oC. The product powder was characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscope (TEM) and Brunauer – Emmett – Teller (BET) techniques. The results indicate that the product was vanadium carbide having particle size of about 30 nm with high surface area.

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 Polyvinyl chloride Waste as an Adsorbent for the Sorption ofPb2+from Aqueous Solution

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Donbebe Wankasi ◽  
Ezekiel Dixon Dikio
Keyword(s):  
Polyvinyl Chloride ◽  
High Surface ◽  
High Surface Area ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffusion Controlled ◽  
The Fourier Transform ◽  
Morphological Image

The sorption of Pb2+from solution by polyvinyl chloride waste was investigated. The morphological features of the polymer sample were studied using the energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), and the Fourier transform infrared spectroscopy (FTIR). Equilibrium, kinetic, and thermodynamic batch adsorption experiments were carried out by the concentration, time, and temperature effects, respectively. The morphological image of the polymer showed irregular small size particles which indicated a high surface area and porosity that facilitated sorption. The adsorption studies recorded relatively rapid uptake of Pb2+by the polymer which was mainly diffusion controlled and followed a second order kinetic process. The thermodynamic studies suggested relatively low temperature (low energy) favoured sorption which was exothermic with a physisorption mechanism.

scholarly journals Fabrikasi Nanotubes Titanium Dioksida (TiO2) Menggunakan Metode Hidrotermal

2017 ◽  
Vol 3 (1) ◽  
pp. 20-26
Author(s):  
Atik Setyani ◽  
Emas Agus Prastyo Wibowo
Keyword(s):  
Tio2 Nanoparticles ◽  
Tio2 Nanotubes ◽  
Crystal Size ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Nanotubes received great attention because it has a high surface area. In this study, TiO2 nanotubes fabricated via hydrothermal method from  synthesis of TiO2 nanoparticles via sol-gel method. Catalysts that have been synthesized later in the characterization by X-Ray Diffraction (XRD) to obtain the crystal size and crystallinity. Crystal size of TiO2 nanoparticles at a temperature of 450C is 13.78 nm. Then characterized by Transmission Electron Microscopy (TEM) to look at the formation of nanotubes. Characterization of TiO2 nanotubes with TEM shows that the structure of the tubes had already been formed TNTs although the growth has not been perfect. It can be seen from the structure TNTs who tend to be short and yet so irregular.DOI: http://dx.doi.org/10.15408/jkv.v0i0.5036  

scholarly journals Preparation of Ammonia Dealuminated Metakaolinite and Its Adsorption against Bixin

2020 ◽  
Vol 20 (4) ◽  
pp. 791
Author(s):  
Winda Rahmalia ◽  
Jean-Francois Fabre ◽  
Thamrin Usman ◽  
Zéphirin Mouloungui
Keyword(s):  
Surface Area ◽  
Room Temperature ◽  
High Surface ◽  
High Surface Area ◽  
Total Pore Volume ◽  
Adsorption Properties ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pseudo Second Order

This study aims to prepare dealuminated metakaolinite which has a high surface area by using NH4OH as an activator. The natural kaolinite sample was treated at 600 °C for 6 h in order to obtain metakaolinite. A dealuminated metakaolinite was then prepared by the repeated activation method using concentrated ammonia (5 M NH4OH) at room temperature. Depending on the nature of each type of material, natural kaolinite, NH4OH treated kaolinite, metakaolinite and NH4OH treated metakaolinite were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET-N2) measurements. XRD and FTIR results confirmed that structural transformation from kaolinite to metakaolinite had occurred. According to SEM-EDS data, the activation of metakaolinite by NH4OH allowed the dealumination of metakaolinite. The increase in the Si/Al ratio was almost twice as high as in kaolinite. BET-N2 analysis showed that the specific surface area and the total pore volume increased significantly after activation. Its adsorption properties were tested against bixin. Bixin adsorption on dealuminated metakaolinite followed pseudo-second order kinetic where k2 = 0.20 g/mg min. The adsorption isotherm followed the Langmuir model where qm = 0.72 mg/g.

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