scholarly journals Titanate Nanotubes as Futuristic Catalyst Support Material

2021 ◽  
Vol 10 (12) ◽  
pp. 24-27
Author(s):  
Dr. Lucky Sikhwivhilu ◽  
◽  
Dr. Venkataraman Vishwanathan ◽  
Keyword(s):  
Surface Composition ◽  
Ageing Time ◽  
Catalyst Support ◽  
Titanate Nanotubes ◽  
X Ray Diffraction ◽  
Time Intervals ◽  
X Ray ◽  
Transmission Electron ◽  
Base Solution ◽  
Degussa P25

Titanate Nanotubes (TNT) were synthesized by aging commercial titanium dioxide (TiO2 - Degussa P25) with an alkali (KOH) solution at different time intervals. The prepared materials were investigated for their surface composition and textural behaviour by X-ray powder diffraction (XRD), Raman spectroscopy, Gas (N2 and CO2) adsorption measurements, and Transmission electron microscopy (TEM). The X-ray diffraction spectra revealed the decrease in the crystalline nature of the materials decreased by exposing them for a longer duration in the base solution. Raman spectra results showed that ageing time affected the structural properties. The specific surface area and the pore size of the newly synthesised materials were affected by the ageing process. The TEM images showed the influence of ageing during the formation of titanate nanotubes. HRTEM revealed that Pd particle sizes of <1 nm was present inside the tubes.

scholarly journals Titanate Nanotubes as Futuristic Catalyst Support Material

2021 ◽  
Vol 10 (12) ◽  
pp. 24-27
Author(s):  
Dr. Lucky Sikhwivhilu ◽  
◽  
Dr. Venkataraman Vishwanathan ◽  
Keyword(s):  
Surface Composition ◽  
Ageing Time ◽  
Catalyst Support ◽  
Titanate Nanotubes ◽  
X Ray Diffraction ◽  
Time Intervals ◽  
X Ray ◽  
Transmission Electron ◽  
Base Solution ◽  
Degussa P25

Titanate Nanotubes (TNT) were synthesized by aging commercial titanium dioxide (TiO2 - Degussa P25) with an alkali (KOH) solution at different time intervals. The prepared materials were investigated for their surface composition and textural behaviour by X-ray powder diffraction (XRD), Raman spectroscopy, Gas (N2 and CO2) adsorption measurements, and Transmission electron microscopy (TEM). The X-ray diffraction spectra revealed the decrease in the crystalline nature of the materials decreased by exposing them for a longer duration in the base solution. Raman spectra results showed that ageing time affected the structural properties. The specific surface area and the pore size of the newly synthesised materials were affected by the ageing process. The TEM images showed the influence of ageing during the formation of titanate nanotubes. HRTEM revealed that Pd particle sizes of <1 nm was present inside the tubes.

scholarly journals Dual Light- and pH-Responsive Composite of Polyazo-Derivative Grafted Cellulose Nanocrystals

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1725 ◽  
Author(s):  
Xiaohong Liu ◽  
Ming Li ◽  
Xuemei Zheng ◽  
Elias Retulainen ◽  
Shiyu Fu
Keyword(s):  
Cellulose Nanocrystals ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
X Ray Diffraction ◽  
Responsive Materials ◽  
X Ray ◽  
Ph Response ◽  
Transmission Electron ◽  
Ft Ir ◽  
Hexyl Methacrylate

As a type of functional group, azo-derivatives are commonly used to synthesize responsive materials. Cellulose nanocrystals (CNCs), prepared by acid hydrolysis of cotton, were dewatered and reacted with 2-bromoisobuturyl bromide to form a macro-initiator, which grafted 6-[4-(4-methoxyphenyl-azo) phenoxy] hexyl methacrylate (MMAZO) via atom transfer radical polymerization. The successful grafting was supported by Fourier transform infrared spectroscopy (FT-IR) and Solid magnetic resonance carbon spectrum (MAS 13C-NMR). The morphology and surface composition of the poly{6-[4-(4-methoxyphenylazo) phenoxy] hexyl methacrylate} (PMMAZO)-grafted CNCs were confirmed with Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The grafting rate on the macro-initiator of CNCs was over 870%, and the polydispersities of branched polymers were narrow. The crystal structure of CNCs did not change after grafting, as determined by X-ray diffraction (XRD). The polymer PMMAZO improved the thermal stability of cellulose nanocrystals, as shown by thermogravimetry analysis (TGA). Then the PMMAZO-grafted CNCs were mixed with polyurethane and casted to form a composite film. The film showed a significant light and pH response, which may be suitable for visual acid-alkali measurement and reversible optical storage.

Carbon Supported Pt+Os Catalysts for Methanol Oxidation

2002 ◽  
Vol 57 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Gülsün Gökağaç ◽  
Brendan J. Kennedy
Keyword(s):  
Methanol Oxidation ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Carbon Support ◽  
Methanol Oxidation Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Metal Metal ◽  
Metal Support

11% Pt/C, 10% Pt + 1%Os/C, 9% Pt + 2%Os/C, 8% Pt + 3%Os/C, 7% Pt + 4%Os/C, 6% Pt + 5%Os/C and 5%Pt + 6% Os/C catalysts have been prepared for methanol oxidation reaction. Transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and cyclic voltammetry have been used to understand the nature of the species present in these catalysts. 7% Pt + 4% Os/C was the most active catalyst, while 8% Pt + 3% Os/C was the least active one. It is found that the metal particle size and distribution on the carbon support, the surface composition and the oxidation states of the metal particles, the metal-metal and metal support interactions are important parameters to define the activity of the catalyst.

scholarly journals Pt Nanocluster Co-Catalysts for Photocatalytic Water Splitting

2018 ◽  
Vol 4 (4) ◽  
pp. 64 ◽  
Author(s):  
Cameron Shearer ◽  
Jason Alvino ◽  
Munkhbayar Batmunkh ◽  
Gregory Metha
Keyword(s):  
Catalyst Activity ◽  
X Ray Diffraction ◽  
Co Catalyst ◽  
X Ray ◽  
Pt Nanoclusters ◽  
Co Catalysts ◽  
Transmission Electron ◽  
Degussa P25 ◽  
Commercial Source ◽  
Photocatalytic Reactions

Degussa P25 is a benchmark form of TiO2 used worldwide in photocatalysis studies. Currently, no such benchmark exists for co-catalysts, which are essential for many photocatalytic reactions. Here, we present the preparation of Pt nanocluster co-catalysts on TiO2 using an unmodified commercial source and equipment that is commonly available. Transmission electron microscopy reveals that the procedure produces TiO2 decorated with Pt atoms and nanoclusters (1–5 atoms). Optical reflectance and X-ray diffraction measurements show that the procedure does not affect the TiO2 polymorph or ultraviolet-visible (UV-Vis) absorbance. Gas phase photocatalytic splitting of heavy water (D2O) shows that the Pt nanocluster-decorated TiO2 outperforms Pt nanoparticle (produced by photodeposition) decorated TiO2 in D2 production. Pt nanoclusters, produced directly from a commercial source, with high co-catalyst activity, are prime candidates to be used in benchmark photocatalytic reactions.

Solvothermal Synthesis of Novel 3D Peony-Like TiO2 Microstructures and its Enhanced Photocatalytic Activity

NANO ◽  
2018 ◽  
Vol 13 (05) ◽  
pp. 1850056 ◽  
Author(s):  
Yugan He ◽  
Qi Yan ◽  
Xiaoyu Chang ◽  
Meiying Zhu ◽  
Weiwei Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Reaction Time ◽  
Uv Light ◽  
X Ray Diffraction ◽  
Reaction Parameters ◽  
X Ray ◽  
Uv Light Irradiation ◽  
Transmission Electron ◽  
Irradiation Power ◽  
Degussa P25

A TiO2 photocatalyst with peony-like microstructures and a large percentage of exposed {001} facets was synthesized using a facile solvethermal method. The peony-like TiO2 was obtained using HF as a capping agent, TiCl4 as the precursor and ethanol as the solvothermal agent. The parameters which influence the mophology and formation mechanism of the products including the HF concentration, the reaction time and temperature and the solvothermal solvent, were investigated. The samples were characterized using field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction and N2 adsorption and desorption analysis. As the reaction time or reaction temperature increased, the morphology TiO2 changed from hexagonally assembled microspheres to peony-like microflowers which were composed of stacks of ultrathin nanosheets. The other reaction parameters also play a crucial role in the formation of the TiO2 microstuctures. Photocatalytic experiments showed that the synthesized TiO2 outperformed Degussa P25 in the photodegradation of methelene blue under a very weak UV light irradiation (power: 8[Formula: see text]W, light intensity: 0.4[Formula: see text]mW[Formula: see text]cm[Formula: see text]).

scholarly journals Pt Nanocluster Co-Catalysts for Photocatalytic Water Splitting

2018 ◽  
Author(s):  
Cameron Shearer ◽  
Jason F. Alvino ◽  
Munkhbayar Batmunkh ◽  
Gregory Metha
Keyword(s):  
Catalyst Activity ◽  
X Ray Diffraction ◽  
Co Catalyst ◽  
X Ray ◽  
Pt Nanoclusters ◽  
Co Catalysts ◽  
Transmission Electron ◽  
Degussa P25 ◽  
Commercial Source ◽  
Photocatalytic Reactions

Degussa P25 is a benchmark form of TiO2 used worldwide in photocatalysis studies. Currently no such benchmark exists for co-catalysts, which are essential for many photocatalytic reactions. Here, we present the preparation of Pt nanocluster co-catalysts on TiO2 using an unmodified commercial source and equipment that is commonly available. Transmission electron microscopy reveals that the procedure produces TiO2 decorated with Pt atom and nanoclusters (1-5 atoms). Optical reflectance and X-ray diffraction measurements show that the procedure does not affect the TiO2 polymorph or UV-Vis absorbance. Gas phase photocatalytic splitting of heavy water (D2O) shows that the Pt nanocluster decorated TiO2 outperforms Pt nanoparticle (produced by photodeposition) decorated TiO2 in D2 production. Pt nanoclusters, produced directly from a commercial source, with high co-catalyst activity are prime candidates to be used in benchmark photocatalytic reactions.

Calcium carbonate microparticle growth controlled by a conjugate drug–copolymer and crystallization time

2014 ◽  
Vol 70 (2) ◽  
pp. 227-235 ◽  
Author(s):  
Florica Doroftei ◽  
Mariana Dana Damaceanu ◽  
Bogdan C. Simionescu ◽  
Marcela Mihai
Keyword(s):  
Electrostatic Interactions ◽  
Ageing Time ◽  
Crystallization Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optical Scanning ◽  
Polymer Conjugate ◽  
Transmission Electron ◽  
Particle Size Increase ◽  
Influence Of Crystallization

The influence of crystallization reaction time on CaCO3microparticle growth from supersaturate aqueous solutions, in the presence of a conjugate drug–copolymer, has been investigated. The polymer conjugate, P(NVP-MA-Ox), is based on poly(N-vinylpyrrolidone–co-maleic anhydride) as the support and 2-amino-5-(4-methoxyphenyl)-1,3,4-oxadiazole as the drug. The microparticles are characterized by optical, scanning and transmission electron microscopy, dynamic light scattering, X-ray diffraction, flow particle image analysis and particle charge density. X-ray diffraction (XRD) investigations showed that calcite polymorph content increased with an increase in crystallization time, even if the electrostatic interactions between Ca2+and polyanionic sites of P(NVP-MA-Ox) structure conduct to an increased vaterite phase stability. The strong particle size increase after 6 h of ageing can be ascribed to partially vaterite recrystallization and adsorption of nano-scaled calcite crystallite nuclei at microparticles surfaces. The pH stability of the particles was shown by zeta potential changes and their adsorption capacity as a function of their composition, and characteristics were tested using methylene blue. The sorption capacity of composite materials was strongly influenced by the ratio between polymorphs in the composites, and increased with the increase of calcite content and ageing time.

scholarly journals Hydrothermal synthesis of monocopper sulfide for hydrogen peroxide-assisted photodegradation of paraquat

2020 ◽  
Vol 26 (1) ◽  
Author(s):  
Rattabal Khunphonoi ◽  
Kitirote Wantala ◽  
Nurak Grisdanurak
Keyword(s):  
Photoelectron Spectroscopy ◽  
Reaction Rate ◽  
Ageing Time ◽  
Reaction Rate Constant ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Energy Band Gap ◽  
X Ray ◽  
Synthesis Parameters ◽  
Transmission Electron

Copper sulfide was prepared by a hydrothermal method at 130°C. The copper to sulfur molar ratio (6-10) and ageing time (24-72 h) were their synthesis parameters. The obtained materials were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscope (TEM), UV-DR spectroscopy and X-ray photoelectron spectroscopy (XPS). In order to obtain monocopper sulfide, CuS, named as covellite, the molar recipe ratio of sulfur to copper should be less than 8 in any hydrothermal ageing time. The morphology showed spherical-like structure with energy band gap of 1.88-2.04 eV. CuS was tested for its photocatalytic degradation of paraquat under visible light irradiation. It exhibited excellent activities in the presence of H<sub>2</sub>O<sub>2</sub>. The kinetic of paraquat degradation was also investigated using Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. The reaction rate constant was three times higher than TiO<sub>2</sub> under the same studied conditions.

Synthesis and Photo-Catalytic Properties Characterization of Graphene/TiO2 Nanotube Composites

2013 ◽  
Vol 544 ◽  
pp. 21-24
Author(s):  
Cai Xia Li ◽  
Lin Zhang ◽  
Dan Yu Jiang ◽  
Qiang Li
Keyword(s):  
Catalytic Properties ◽  
Raw Materials ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Nanotube Composites ◽  
Degussa P25 ◽  
Concentrated Solution

Selecting graphene oxide (GO) and the Degussa P25 TiO2 (80% anatase and 20% rutile) as raw materials, the composites of graphene/TiO2 nano-tubes were simply and quickly prepared under the conditions of a concentrated solution of sodium hydroxide. The as-obtained composites’ phase structure was analyzed and characterized by powder X-ray diffraction (XRD), their morphologies were also observed and cross-confirmed under the Transmission Electron Microscopy (TEM). The measurements showed that the composites prepared in this work have a remarkable structure, and compared to the seperate TiO2 nano-tubes, the agglomeration of TiO2 nano-tubes covered on the surface of the graphene is apparently not so serious. In view of this, we preliminary tested the composites’ photo-catalytic performance with the visible light irradiation, and also made a comparison with TiO2 nano-tubes.

Synthesis of Carbon Onions with High Purity by Chemical Vapor Deposition

2013 ◽  
Vol 641-642 ◽  
pp. 43-46
Author(s):  
Lei Shan Chen ◽  
Cun Jing Wang
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Carbon Materials ◽  
Catalyst Support ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Carbon Onions ◽  
Nano Carbon

Nano-carbon materials were synthesized by decomposing acetylene at 400 °C using iron supported on alumina as catalyst. The catalysts contain about 0.3 and 5.2 wt% iron. The products were refluxed in concentrated HCl at 80°C for 36 h in order to remove the catalyst support. The samples were examined by transmission electron microscopy and X-ray diffraction. The results show that carbon onions surrounding Fe3C core were obtained using the catalyst containing 0.3 wt% iron and these carbon onions had a structure of stacked graphitic fragments, with diameters in the range 15-50 nm.

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