Surface Models of Alumina Supported Copper Oxide Prepared by Laser Ablation: Dispersion and Electron Structure Changes Following Reduction and Oxidation Cycles

1994 ◽  
Vol 368 ◽  
Author(s):  
B. Hirschauer ◽  
J. Paul
Keyword(s):  
Laser Ablation ◽  
Copper Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Electron Structure ◽  
Hydroxyl Groups ◽  
Thermal Treatments ◽  
Surface Hydroxyl ◽  
Structure Changes ◽  
Surface Models

ABSTRACTWe have explored and developed laser ablation as a tool to synthesize realistic planar models of high surface area catalysts as well as novel materials, not accessible with wet chemical methods. The process is illustrated by data for dispersion and electron structure modifications following thermal treatments of alumina supported copper oxide. Planar models of different wet and dry carrier/overlayer combinations were prepared and exposed to oxidizing and reducing atmosphere at 500°C. Characterization was made by XPS/ESCA. The data reveal the importance of surface hydroxyl groups in the two initial components to control coalescence and interdiffusion. The ablation route is part of our ongoing DENOX project and comparisons are made with other materials, tested for their materials properties and catalytic behavior in HC/NO reactions.

Crystal Structure, Short-Range Oxygen Defects, and Water Adsorption in La- and Nd-Modified ZrO2

1994 ◽  
Vol 376 ◽  
Author(s):  
C.-K. Loong ◽  
J. W. Richardson ◽  
L. E. Iton ◽  
M. Ozawa
Keyword(s):  
Crystal Structure ◽  
Inelastic Neutron Scattering ◽  
High Surface ◽  
High Surface Area ◽  
Inelastic Neutron ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Oxygen Defects ◽  
Surface Hydroxyl Groups

ABSTRACTDoping Rare-earth (RE) elements to ZrO2 helps stabilize the cubic and tetragonal phases and improves resistance to thermal shock and sintering at high temperatures. Since a RE ion has a lower valency (3+) than Zr ion (4+), oxygen vacancies are formed to preserve electroneutrality. We have studied the crystal structure of La0.1Zro.9O1.95 and Nd0.1Zr0.9O1.95 by neutron diffraction and examined the associated oxygen defects by a Fourier transform of the filtered residual diffuse scattering. The hydration process was investigated by inelastic neutron-scattering measurements of the hydrogen vibrational density of states of the surface hydroxyl groups and physisorbed water on these fine powders. We compare the O-H stretch vibrations from samples with only surface hydroxyl groups to multilayer coverage of water molecules. The decreasing energies and increasing widths of the O-H stretch bands with increasing H2O coverage indicate the influence of hydrogen bonding on the motion of water molecules. Similar elastic and inelastic experiments were also performed on a high surface-area pure ZrO2 powder.

NANOCELLULOSE AND ITS POTENTIAL USE FOR SUSTAINABLE INDUSTRIAL APPLICATIONS

2020 ◽  
Vol 50 (2) ◽  
pp. 59-64
Author(s):  
Carlos Negro ◽  
Ana Balea Martín ◽  
Jose Luis Sanchez-Salvador ◽  
Cristina Campano ◽  
Elena Fuente ◽  
...  
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Industrial Applications ◽  
High Reactivity ◽  
Environmental Benefits ◽  
Hydroxyl Groups ◽  
Paper Briefly ◽  
Potential Availability ◽  
Potential Use ◽  
Market Perspective

Nanocellulose (NC) and its wide applications have attracted high attention due to its desirable properties such as high surface area, extraordinary mechanical properties, high reactivity and easy modification of NC surface due to the presence of primary hydroxyl groups. NC also presents several environmental benefits, including high potential availability because its production is coming from natural sources, renewability and nontoxicity. This paper briefly summarizes some of the activities of the research group “Cellulose, Paper and Water Advanced Treatments” from Complutense University of Madrid that were presented in CAIQ 2019, including the main types of NC, the production processes and their characterization. Additionally, the most promising NC applications are described such as for paper and board, for wastewater treatment, food and cement-based materials. Moreover, a market perspective of NC is also presented.

The synthesis of bayberry-like mesoporous TiO2 microspheres by a kinetics-controlled method and their hydrophilic films

CrystEngComm ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 969-978 ◽  
Author(s):  
Li Li ◽  
Liang Wang ◽  
Xinhong Chen ◽  
Changyuan Tao ◽  
Jun Du ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Surface ◽  
Mesoporous Tio2 ◽  
High Density ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
High Surface Roughness ◽  
Surface Hydroxyl Groups ◽  
Tio2 Microspheres

Bayberry-like mesoporous TiO2 hydrophilic films with high surface roughness and high density of surface hydroxyl groups.

scholarly journals New Insights for the Future Design of Composites Composed of Hydrochar and Zeolite for Developing Advanced Biofuels from Cranberry Pomace

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6600
Author(s):  
Omid Norouzi ◽  
Mohammad Heidari ◽  
Mario M. Martinez ◽  
Animesh Dutta
Keyword(s):  
High Surface ◽  
Coke Formation ◽  
High Surface Area ◽  
Chemical Properties ◽  
Catalytic Performance ◽  
Hydroxyl Groups ◽  
Advanced Biofuels ◽  
Operational Conditions ◽  
Future Design ◽  
Cellulosic Sugars

This study provides fundamental insight and offers a promising catalytic hydrothermal method to harness cranberry pomace as a potential bioenergy and/or hydrochar source. The physical and chemical properties of Canadian cranberry pomace, supplied by Fruit d’Or Inc., were examined and the optimum operational conditions, in terms of biocrude yield, were obtained by the I-optimal matrix of Design Expert 11. Afterward, cranberry pomace hydrochar (CPH) and zeolite were separately introduced to the hydrothermal liquefaction (HTL) process to investigate the benefits and disadvantages associated with their catalytic activity. CPH was found to be a better host than zeolite to accommodate cellulosic sugars and showed great catalytic performance in producing hydrocarbons. However, high amounts of corrosive amino and aliphatic acids hinder the practical application of CPH as a catalyst. Alternatively, zeolite, as a commercial high surface area catalyst, had a higher activity for deoxygenation of compounds containing carbonyl, carboxyl, and hydroxyl groups than CPH and resulted in higher selectivity of phenols. Due to the low hydrothermal structural stability, coke formation, and narrow pore size distribution, further activations and modifications are needed to improve the catalytic behavior of zeolite. Our results suggest that a composite composed of CPH and zeolite can resolve the abovementioned limitations and help with the development and commercialization of advanced biofuels from cranberry pomace.

scholarly journals Synthesis of Wollastonite Powders by Combustion Method: Role of Amount of Fuel

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Imarally V. de S. R. Nascimento ◽  
Willams T. Barbosa ◽  
Raúl G. Carrodeguas ◽  
Marcus V. L. Fook ◽  
Miguel A. Rodríguez
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Combustion Process ◽  
Calcium Nitrate ◽  
Combustion Method ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Solution Combustion

The objective of this work has been the synthesis of wollastonite by solution combustion method. The novelty of this work has been obtaining the crystalline phase without the need of thermal treatments after the synthesis. For this purpose, urea was used as fuel. Calcium nitrate was selected as a source of calcium and colloidal silica served as a source of silicon. The effect of the amount of fuel on the combustion process was investigated. Temperature of the combustion reaction was followed by digital pyrometry. The obtained products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and specific surface area. The results showed that the combustion synthesis provides nanostructured powders characterized by a high surface area. When excess of urea was used, wollastonite-2M was obtained with a submicronic structure.

scholarly journals Adhesion of cells to polystyrene surfaces.

1983 ◽  
Vol 97 (5) ◽  
pp. 1500-1506 ◽  
Author(s):  
A S Curtis ◽  
J V Forrester ◽  
C McInnes ◽  
F Lawrie
Keyword(s):  
Cell Adhesion ◽  
Sulfuric Acid ◽  
High Surface ◽  
Attenuated Total Reflection ◽  
Hydroxyl Groups ◽  
Kidney Cells ◽  
Baby Hamster Kidney ◽  
Surface Hydroxyl ◽  
Sulfur Containing ◽  
Baby Hamster Kidney Cells

The surface treatment of polystyrene, which is required to make polystyrene suitable for cell adhesion and spreading, was investigated. Examination of surfaces treated with sulfuric acid or various oxidizing agents using (a) x-ray photoelectron and attenuated total reflection spectroscopy and (b) measurement of surface carboxyl-, hydroxyl-, and sulfur-containing groups by various radiochemical methods showed that sulfuric acid produces an insignificant number of sulfonic acid groups on polystyrene. This technique together with various oxidation techniques that render surfaces suitable for cell culture generated high surface densities of hydroxyl groups. The importance of surface hydroxyl groups for the adhesion of baby hamster kidney cells or leukocytes was demonstrated by the inhibition of adhesion when these groups were blocked: blocking of carboxyl groups did not inhibit adhesion and may raise the adhesion of a surface. These results applied to cell adhesion in the presence and absence of serum. The relative unimportance of fibronectin for the adhesion and spreading of baby hamster kidney cells to hydroxyl-rich surfaces was concluded when cells spread on such surfaces after protein synthesis was inhibited with cycloheximide, fibronectin was removed by trypsinization, and trypsin activity was stopped with leupeptin.

scholarly journals Comparison of Surface-Bound and Free-Standing Variations of HKUST-1 MOFs: Effect of Activation and Ammonia Exposure on Morphology, Crystallinity, and Composition

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 650 ◽  
Author(s):  
Brandon Bowser ◽  
Landon Brower ◽  
Monica Ohnsorg ◽  
Lauren Gentry ◽  
Christopher Beaudoin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Surface ◽  
High Surface Area ◽  
Free Standing ◽  
Guest Molecules ◽  
X Ray ◽  
Ammonia Uptake ◽  
Multiple Exposures ◽  
Structure Changes ◽  
Ammonia Exposure

Metal-organic frameworks (MOFs) are extremely porous, crystalline materials with high surface area for potential use in gas storage, sequestration, and separations. Toward incorporation into structures for these applications, this study compares three variations of surface-bound and free-standing HKUST-1 MOF structures: surface-anchored MOF (surMOF) thin film, drop-cast film, and bulk powder. Herein, effects of HKUST-1 ammonia interaction and framework activation, which is removal of guest molecules via heat, are investigated. Impact on morphology and crystal structure as a function of surface confinement and size variance are examined. Scanning probe microscopy, scanning electron microscopy, powder X-ray diffraction, Fourier-transform infrared spectroscopy, and energy dispersive X-ray spectroscopy monitor changes in morphology and crystal structure, track ammonia uptake, and examine elemental composition. After fabrication, ammonia uptake is observed for all MOF variations, but reveals dramatic morphological and crystal structure changes. However, activation of the framework was found to stabilize morphology. For activated surMOF films, findings demonstrate consistent morphology throughout uptake, removal, and recycling of ammonia over multiple exposures. To understand morphological effects, additional ammonia exposure experiments with controlled post-synthetic solvent adsorbates were conducted utilizing a HKUST-1 standard powder. These findings are foundational for determining the capabilities and limitation of MOF films and powders.

Effect of Pretreatment of Synthetic and Natural Carbons as Starting Materials for Carbon Nanotubes

2005 ◽  
Vol 23 ◽  
pp. 285-288 ◽  
Author(s):  
N. Buang ◽  
M. Aziz ◽  
S. Sanip ◽  
J.C. Tee ◽  
Z.H.Z Abidin ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Energy Storage And Conversion ◽  
Thermal Treatments ◽  
Active Materials ◽  
And Chemical Properties

Carbon are well known as active materials for energy storage and conversion. They are preferred because carbon materials have high electrical conductivity, low cost, high surface area, porosity, formability and possess good chemical and electrochemical resistivity. The most recently discovered novel carbon material is the carbon nanotubes, having unique geometrical structure and stable mechanical and chemical properties. The starting materials for carbon nanotubes production widely used are high purity graphite. Thus, two types of carbons were studied and thermal treatments were conducted at temperatures ranging from 600 – 800 °C for several hours. The effect of the pretreatment upon their morphology and surface area were looked into. It was found that significant changes occurred for the natural carbons while the synthetic carbons showed little or no changes at the particular temperature range. The thermal treatment has resulted in the exposure of fresh edge planes and microparticles as well as changes in the specific surface area and enhances their adsorption properties.

Hydroxyl-rich nanoporous carbon nanosheets synthesized by a one-pot method and their application in the in situ preparation of well-dispersed Ag nanoparticles

RSC Advances ◽  
2015 ◽  
Vol 5 (116) ◽  
pp. 96062-96066 ◽  
Author(s):  
Xiaodi Guo ◽  
Gaili Liu ◽  
Shuang Yue ◽  
Jing He ◽  
Lianying Wang
Keyword(s):  
Ag Nanoparticles ◽  
High Surface ◽  
High Surface Area ◽  
Nanoporous Carbon ◽  
Hydroxyl Groups ◽  
Ag Nps ◽  
One Pot ◽  
Carbon Nanosheets ◽  
In Situ Preparation

Nanoporous carbon nanosheets (CNSs) with high surface area have been synthesized by pyrolysis of organic–inorganic precursor. The CNSs with rich hydroxyl groups display remarkable reactivity and capability for in situ loading ultrafine Ag NPs.

Synthesis of a Low-Density Copper Oxide Monolithic Aerogel Using Inorganic Salt Precursor

2011 ◽  
Vol 217-218 ◽  
pp. 1165-1169
Author(s):  
Yu Tie Bi ◽  
Hong Bo Ren ◽  
Lin Zhang
Keyword(s):  
Electron Microscopy ◽  
Copper Oxide ◽  
Inorganic Salt ◽  
Copper Chloride ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Low Density ◽  
High Porosity ◽  
Different Temperatures

Copper oxide monolithic aerogel was prepared by sol–gel method using inorganic salt as precursor, ethanol as the solvent, and propylene oxide as the gelation agent. Calcination of the as-prepared aerogels at different temperatures induced a phase change which resulted in the formation of a mesoporous copper oxide aerogels. Field emission scanning electron microscopy (FESEM), Highresolution transmission electron microscopy (HRTEM), and Brunauer-Emmett-Teller(BET) methods were used to characterize the as-prepared aerogels. The combined results indicated that the as-prepared CuO aerogel has high porosity, high surface area, and low density. The X-ray diffraction (XRD) patterns show that the as-prepared CuO aerogel is highly crystalline and is identified to be predominantly copper chloride hydroxide, Cu2Cl(OH)3。

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