Effects of Surfactant Concentration on the Microstructures of TiO2 Hollow Spheres by Hydrothermal Method

2013 ◽  
Vol 634-638 ◽  
pp. 2189-2192 ◽  
Author(s):  
Lian Ying Lu ◽  
Lin Xu ◽  
Ting Ting Yin ◽  
Guo Hong Wang
Keyword(s):  
Hydrothermal Method ◽  
Surface Area ◽  
High Surface ◽  
Photovoltaic Cells ◽  
Hollow Spheres ◽  
High Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hollow Structures ◽  
Good Penetration

TiO2 hollow spheres were prepared by hydrothermal method using CTAB, glucose and (NH4)2TiF6 as surfactant, template and titanium source, respectively. The microstructures of hollow spheres TiO2 were characterized with X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared (FTIR). The results showed the concentration of the CTAB obviously influenced the morphology of hollow spheres TiO2. This synthesis route may also extend to the preparation of hollow structures of other metal oxides. Because of the large specific surface area, porous structure, and good penetration, the hierarchical TiO2-derived hollow spheres may find great applications in catalysis, photovoltaic cells and high surface area electrodes.

Synthesis and capacitive properties of carbonaceous sphere@MnO2 rattle-type hollow structures

2010 ◽  
Vol 25 (8) ◽  
pp. 1476-1484 ◽  
Author(s):  
Jintao Zhang ◽  
Jizhen Ma ◽  
Jianwen Jiang ◽  
X.S. Zhao
Keyword(s):  
Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
Hollow Spheres ◽  
High Surface Area ◽  
Mesoporous Structure ◽  
Experimental Conditions ◽  
X Ray ◽  
Hollow Structures ◽  
Capacitive Properties

Carbonaceous sphere@MnO2 rattle-type hollow spheres were synthesized under mild experimental conditions. The as-prepared hollow structures were characterized using scanning electron microscope, transmission electron microscope, x-ray diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, and nitrogen adsorption techniques. The characterization data showed the formation of rattle-type hollow structures with a mesoporous MnO2 shell and a carbonaceous sphere core. The composition and shell thickness of the hollow spheres can be controlled experimentally. The capacitive performance of the hollow structures was evaluated by using both cycle voltammetry and charge–discharge methods. The results demonstrated a specific capacitance as high as 184 F/g at a current density of 125 mA/g. The good electrocapacitive performance resulted from the mesoporous structure and high surface area of the MnO2-based hollow spheres.

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.

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.

scholarly journals Growth of Hierarchically Structured High-Surface Area Alumina on FeCrAl Alloy Wires

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Chandni Rallan ◽  
Aaron Akah ◽  
Patrick Hill ◽  
Arthur Garforth
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
X Ray Diffraction ◽  
Entire Study ◽  
X Ray ◽  
Thermogravimetric Analyzer ◽  
Fecral Alloy ◽  
Time Periods ◽  
Metastable Alumina

The formation of metastable alumina phases due to the oxidation of commercial FeCrAl alloy wires (0.5 mm thickness) at various temperatures and time periods has been examined. Samples were isothermally oxidised in air using a thermogravimetric analyzer (TGA). The morphology of the oxidised samples was analyzed using an Electronic Scanning Electron Microscope (ESEM) and X-ray on the surface analysis was done using an Energy Dispersive X-Ray (EDX) analyzer. The technique of X-Ray Diffraction (XRD) was used to characterize the phase of the oxide growth. The entire study showed that it was possible to grow high-surface area gamma alumina on the FeCrAl alloy wire surfaces when isothermally oxidised above 800°C over several hours.

Preparation of High Surface Area Ni-SDC Cermets Using a Surfactant-Assisted Co-Precipitation Method

2006 ◽  
Vol 942 ◽  
Author(s):  
Sang Joon Park ◽  
Tae Wook Eom ◽  
Jae Eun Oh ◽  
Hae Kwang Yang ◽  
Kyung Hwan Kim
Keyword(s):  
Surface Area ◽  
Cetyltrimethylammonium Bromide ◽  
High Surface ◽  
High Surface Area ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Two Phases ◽  
Co Precipitation ◽  
Surfactant Assisted

ABSTRACTA surfactant-assisted co-precipitation method was employed for obtaining high surface area Ni-SDC with improved structural properties for SOFC applications. In the work, a cationic surfactant, cetyltrimethylammonium bromide(CTAB) was employed with NiCl2, SmCl3 and CeCl3 as precursors and NH4OH as mineralizer. The elimination of surfactants upon calcination gives rise to the formation of high surface area NiO-SDC. When calcined at 600°C, the powders with surface area of 249 m2/g, were obtained and the pore size was 14.45 nm. The powders consist of two phases, the cubic NiO and SDC confirmed with X-ray diffraction identification.

scholarly journals Syntheses of Nanostructured Magnesium Carbonate Powders with Mesoporous Structures from Carbon Dioxide

2021 ◽  
Vol 11 (3) ◽  
pp. 1141
Author(s):  
Fernando J. Rodríguez-Macías ◽  
José E. Ortiz-Castillo ◽  
Erika López-Lara ◽  
Alejandro J. García-Cuéllar ◽  
José L. López-Salinas ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Magnesium Carbonate ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
Aqueous Synthesis ◽  
Synthesis Time ◽  
X Ray

In this work, we present the results of two synthesis approaches for mesoporous magnesium carbonates, that result in mineralization of carbon dioxide, producing carbonate materials without the use of cosolvents, which makes them more environmentally friendly. In one of our synthesis methods, we found that we could obtain nonequilibrium crystal structures, with acicular crystals branching bidirectionally from a denser core. Both Raman spectroscopy and X-ray diffraction showed these crystals to be a mixture of sulfate and hydrated carbonates. We attribute the nonequilibrium morphology to coprecipitation of two salts and short synthesis time (25 min). Other aqueous synthesis conditions produced mixtures of carbonates with different morphologies, which changed depending on drying temperature (40 or 100 °C). In addition to aqueous solution, we used supercritical carbon dioxide for synthesis, producing a hydrated magnesium carbonate, with a nesquehonite structure, according to X-ray diffraction. This second material has smaller pores (1.01 nm) and high surface area. Due to their high surface area, these materials could be used for adsorbents and capillary transport, in addition to their potential use for carbon capture and sequestration.

scholarly journals Synthesis of high surface area mesoporous silica SBA-15 by adjusting hydrothermal treatment time and the amount of polyvinyl alcohol

2019 ◽  
Vol 17 (1) ◽  
pp. 963-971
Author(s):  
Ridhawati Thahir ◽  
Abdul Wahid Wahab ◽  
Nursiah La Nafie ◽  
Indah Raya
Keyword(s):  
Mesoporous Silica ◽  
Surface Area ◽  
Hydrothermal Treatment ◽  
Pore Volume ◽  
Pore Diameter ◽  
High Surface ◽  
High Surface Area ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
X Ray

AbstractThe high surface area of mesoporous silica SBA-15 has been synthesized successfully by hydrothermal treatment with direct addition of PVA, triblock copolymer (P123) as a direct structure agent and tetraethyl orthosilicate (TEOS) as a precursor. The mesoporous silica SBA-15 have been characterized with nitrogen physisorption, scanning electron microscopy, Fourier transformed infrared spectroscopy, and x-ray diffraction. Measurement of nitrogen sorption indicated that with the addition of PVA, the surface area is increased but the pore volume and pore diameter is not significantly. The short time of hydrothermal treatment (20 h) and using x-ray diffraction, showed that the morphological structure of silica SBA-15 can be changed to a orthorhombic crystal system. The result of the FTIR and SEM-EDX characteristic indicated the functional groups and morphology of the SBA-15 with a narrow pore size distribution. The BET method has exhibited the largest surface area 1726 m2/g, pore volume 1.4 cm3/g, and pore diameter 3.2 nm. It can be suggested that the silica mesoporous SBA-15 will have potential application prospect in catalysis, storage, and adsorbent.

scholarly journals Synthesis, characterization, and reactivity of tungsten oxynitride

1998 ◽  
Vol 13 (8) ◽  
pp. 2321-2327 ◽  
Author(s):  
Toby E. Lucy ◽  
Todd P. St. Clair ◽  
S. Ted Oyama
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
X Ray Diffraction ◽  
Heating Rates ◽  
Continuous Transformation ◽  
X Ray ◽  
Synthesis Conditions ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction

High surface area tungsten oxynitride has been prepared by the temperature programmed reaction (TPR) of WO3 with NH3. All samples were characterized by x-ray diffraction (XRD), nitrogen physisorption, CO chemisorption, and elemental analysis. Samples were prepared at different heating rates (β), and a Redhead analysis yielded an activation energy for nitridation of 109 kJ mol−1. A heating rate of 0.016 K s−1 gave optimal synthesis conditions. Solid state intermediates were studied by interrupting the temperature program at various stages. No distinct suboxide phases were found using XRD. The nitridation step was determined to be a continuous transformation from oxide to oxynitride. Surface area, CO uptake, and nitrogen weight % were all found to increase as the reaction progressed. Reactivity experiments showed reasonable hydrodeoxygenation (HDO) and hydrodenitrogenation (HDN) activity, but little hydrogenation (HYD) or hydrodesulfurization (HDS) activity.

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 Organomineral nanocomposite carbon burial during Oceanic Anoxic Event 2

2014 ◽  
Vol 11 (5) ◽  
pp. 6815-6844
Author(s):  
S. C. Löhr ◽  
M. J. Kennedy
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
X Ray ◽  
Oceanic Anoxic Event ◽  
Carbon Burial ◽  
Anoxic Events ◽  
Mineral Surface Area

Abstract. Organic carbon (OC) enrichment in sediments deposited during Oceanic Anoxic Events (OAEs) is commonly attributed to elevated productivity and marine anoxia. We find that OC enrichment in the late Cenomanian aged OAE2 at Demerara Rise was controlled by co-occurrence of anoxic bottom-water, sufficient productivity to saturate available mineral surfaces and variable deposition of high surface area detrital smectite clay. Redox indicators show consistently oxygen-depleted conditions, while a strong correlation between OC concentration and sediment mineral surface area (R2=0.92) occurs across a range of TOC values from 9–33%. X-ray diffraction data indicates intercalation of OC in smectite interlayers while electron, synchrotron infrared and X-ray microscopy show an intimate association between clay minerals and OC, consistent with preservation of OC as organomineral nanocomposites and aggregates rather than discrete, μm-scale pelagic detritus. Since the consistent ratio between TOC and mineral surface area suggests that excess OC relative to surface area is lost, we propose that it is the varying supply of smectite that best explains variable organic enrichment against a backdrop of continuous anoxia, which is conducive to generally high TOC during OAE2 at Demerara Rise. Smectitic clays are unique in their ability to form stable organomineral nanocomposites and aggregates that preserve organic matter, and are common weathering products of continental volcanic deposits. An increased flux of smectite coinciding with high carbon burial is consistent with evidence for widespread volcanism during OAE2, so that organomineral carbon burial may represent a potential feedback to volcanic degassing of CO2.

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