Oxidation of hydrogels based of sodium alginate and MnO2 as catalyst

In this study, first a hydrogel based on sodium alginate and acrylamide was prepared by radical polymerization method and then manganese oxide was formed in its lattice structure and nanocomposite hydrogels were obtained. In the next step, Nanocomposite hydrogels were used as catalysts for the oxidation of alcohols. To evaluate the physical properties and confirm the structure of nanocomposite hydrogels, Hydrogel swelling tests, FT-IR infrared conversion spectroscopy, TGA Thermal gravimetric, SEM Scanning electron microscopy and TEM Transmission electron microscopy were used. The amount of manganese was measured using an atomic absorption spectrometer. Also, factors affecting oxidation reactions such as reaction temperature, amount of catalyst and reaction time were optimized to achieve the highest percentage of conversion of alcohols to aldehydes. Under optimal conditions, the highest conversion percentage of benzyl alcohol was 79% for Benz aldehyde at 80 °C for 24 hours.

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Pd Nanoparticles Stabilized on the Cross-Linked Melamine-Based SBA-15 as a Catalyst for the Mizoroki–Heck Reaction

Catalysis Letters ◽

10.1007/s10562-021-03691-9 ◽

2021 ◽

Author(s):

Ayat Nuri ◽

Abolfazl Bezaatpour ◽

Mandana Amiri ◽

Nemanja Vucetic ◽

Jyri-Pekka Mikkola ◽

...

Keyword(s):

Electron Microscopy ◽

Inductively Coupled Plasma ◽

High Surface ◽

High Surface Area ◽

Coupling Reaction ◽

Pd Nanoparticles ◽

Significant Activity ◽

Inductively Coupled ◽

Transmission Electron ◽

Ft Ir

AbstractMesoporous SBA-15 silicate with a high surface area was prepared by a hydrothermal method, successively modified by organic melamine ligands and then used for deposition of Pd nanoparticles onto it. The synthesized materials were characterized with infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen physisorption, scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP-OES). The catalyst was effectively used in the Mizoroki–Heck coupling reaction of various reactants in the presence of an organic base giving the desired products in a short reaction time and with small catalysts loadings. The reaction parameters such as the base type, amounts of catalyst, solvents, and the temperature were optimized. The catalyst was easily recovered and reused at least seven times without significant activity losses. Graphic Abstract

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Hydrothermal Synthesis, Characterization and Exploration of Photocatalytic Activities of Polyoxometalate: Ni-CoWO4 Nanoparticles

Crystals ◽

10.3390/cryst11050456 ◽

2021 ◽

Vol 11 (5) ◽

pp. 456

Author(s):

Fahad A. Alharthi ◽

Hamdah S. Alanazi ◽

Amjad Abdullah Alsyahi ◽

Naushad Ahmad

Keyword(s):

Electron Microscopy ◽

Hydrothermal Synthesis ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Structure Morphology ◽

Photocatalytic Activities ◽

Ft Ir ◽

Photocatalytic Reactions ◽

Cobalt Tungstate

This study demonstrated the hydrothermal synthesis of bimetallic nickel-cobalt tungstate nanostructures, Ni-CoWO4 (NCW-NPs), and their phase structure, morphology, porosity, and optical properties were examined using X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), high resolution Transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) and Raman instruments. It was found that as-calcined NCW-NPs have a monoclinic phase with crystal size ~50–60 nm and is mesoporous. It possessed smooth, spherical, and cubic shape microstructures with defined fringe distance (~0.342 nm). The photocatalytic degradation of methylene blue (MB) and rose bengal (RB) dye in the presence of NCW-NPs was evaluated, and about 49.85% of MB in 150 min and 92.28% of RB in 90 min degraded under visible light. In addition, based on the scavenger’s study, the mechanism for photocatalytic reactions is proposed.

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Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.50.18 ◽

2017 ◽

Vol 50 ◽

pp. 18-31 ◽

Cited By ~ 6

Author(s):

Rudzani Sigwadi ◽

Simon Dhlamini ◽

Touhami Mokrani ◽

Patrick Nonjola

Keyword(s):

Electron Microscopy ◽

Particle Size ◽

Zirconium Oxide ◽

Thermo Gravimetric Analysis ◽

Gravimetric Analysis ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Crystallite Sizes ◽

Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

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Study on Nano- and Microcrystallites in Urines of Uric Acid Stone Patients

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.655-657.1927 ◽

2013 ◽

Vol 655-657 ◽

pp. 1927-1930 ◽

Cited By ~ 1

Author(s):

Guang Na Zhang ◽

Zhi Yue Xia ◽

Jian Ming Ouyang ◽

Li Kuan

Keyword(s):

Electron Microscopy ◽

Uric Acid ◽

X Ray Diffraction ◽

Uric Acid Stone ◽

Urine Ph ◽

Stone Formers ◽

Transmission Electron ◽

Close Relationship ◽

Ft Ir ◽

Ft Ir Spectroscopy

The presence of crystallites in urine is closely related to stones formation. In this article, the components, morphology of nano- and micro-crystallites in urines of 20 uric acid (UA) stone formers as well as their relationship with the formation of UAstones were comparatively studied using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The main constituent of urinary crystallites was uric acid. Their particle size distribution was highly uneven, ranging from several nanometers to several tens of micrometers, and obvious aggregation was observed. These results showed that there was close relationship among stone components, urinary crystallites composition and urine pH.

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Improving stability of cerium oxide nanoparticles by microbial polysaccharides coating

Journal of the Serbian Chemical Society ◽

10.2298/jsc171205031m ◽

2018 ◽

Vol 83 (6) ◽

pp. 745-757 ◽

Cited By ~ 6

Author(s):

Ivana Milenkovic ◽

Ksenija Radotic ◽

Branko Matovic ◽

Marija Prekajski ◽

Ljiljana Zivkovic ◽

...

Keyword(s):

Electron Microscopy ◽

Cerium Oxide ◽

Aqueous Media ◽

Suspension Stability ◽

X Ray Diffraction ◽

Synthesis Conditions ◽

Transmission Electron ◽

Ft Ir ◽

Microbial Exopolysaccharides ◽

The Stability

Cerium oxide (CeO2) nanoparticles (CONPs) are interesting biomaterials with various applications in biomedicine, cosmetics and the pharmaceutical industry, but with limited practical application because of their low stability in aqueous media. The aim of this study was to obtain CONPs with increased stability by coating the particles. Microbial exopolysaccharides (levan, pullulan) and glucose were used to prepare CONPs under different synthesis conditions. Coating was attempted by adding the carbohydrates during (direct coating) or after (subsequent coating) the synthesis of CONPs. The obtained nanoparticles were characterized by X-Ray diffraction analysis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The suspension stability of the uncoated and coated CONPs in aqueous media was evaluated by measuring the hydrodynamic size, zeta potential and turbidity. The FT-IR spectra revealed the differences between coated CONPs and showed the success of subsequent coating with carbohydrates. Coating with carbohydrates improved the stability the CONP suspension by decreasing the size of aggregated particles. The suspensions of levan- and glucose-coated CONPs had the best stability. In this study, CONPs were prepared using non-toxic materials, which were completely environmentally friendly. The obtained results open new horizons for CONP synthesis, improving their biological applications.

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Synthesis of Indole Derivatives Using Biosynthesized ZnO-CaO Nanoparticles as an Efficient Catalyst

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.66.61 ◽

2021 ◽

Vol 66 ◽

pp. 61-71

Author(s):

Tahereh Heidarzadeh ◽

Navabeh Nami ◽

Daryoush Zareyee

Keyword(s):

Electron Microscopy ◽

Indole Derivatives ◽

X Ray Diffraction ◽

Efficient Catalyst ◽

X Ray ◽

Transmission Electron ◽

Solvent Free Conditions ◽

Ft Ir ◽

Eggshell Waste ◽

Aromatic And Aliphatic Amines

The principal aim of this research is using biosynthesized ZnO-CaO nanoparticles (NPs) for preparation of indole derivatives. ZnO-CaO NPs have been prepared using Zn(CH3COO)2 and eggshell waste powder in solvent-free conditions. Morphology and structure of NPs were determined by FT-IR, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive spectra (EDS). It was used as a highly efficient catalyst for the synthesis of indole derivatives. Some indole derivatives were synthesized by the reaction of indole, formaldehyde, aromatic and aliphatic amines in the presence of ZnO-CaO NPs (5 mol%) in ethanol under reflux conditions. The assigned structure was further established by CHN analyses, NMR, and FT-IR spectra. Because of excellent capacity, the exceedingly simple workup and good yield, eco-friendly catalyst ZnO-CaO NPs were proved to be a good catalyst for this reaction.

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Microstructure of Interface between Zirconia and Veneer Porcelain

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.492.55 ◽

2011 ◽

Vol 492 ◽

pp. 55-60 ◽

Cited By ~ 1

Author(s):

Bin Deng ◽

Hong Chen Liu ◽

Yuan Fu Yi ◽

Long Quan Shao ◽

Kang Lin Hou ◽

...

Keyword(s):

Electron Microscopy ◽

Surface Composition ◽

Glass Composition ◽

Lattice Structure ◽

Etching Time ◽

Interface Bonding ◽

Transmission Electron ◽

Bonding Property ◽

Amorphous Glass ◽

Tem Transmission Electron Microscopy

To study whether the veneering technique will have an impact on zirconia grain and the bonding type and relationship on interface between zirconia and veneer porcelain. Materials and methods: After sintered, zirconia was annealed for 15 minute to finish the phase transition from m to t.4 types of veneer porcelains were sintered and observed with SEM (scanning electron microscopy) and TEM (transmission electron microscopy). Results: With etching time extending, it appeared that many materials loosed and corrosional pit deepened, enlarged in the veneer porcelain, which made crystallize structure move into veneering surface. Composition of interface mainly was amorphous glass matrix and zirconia. Energy spectrum analysis showed that there was no remnant glass composition in the zirconia side departing from interface. SEM showed that crystal in veneering side did not participate interface bonding. Conclusion: The interface between 4 types of veneer porcelains and zirconia bonded well. Veneering sintering technique didn’t change lattice structure of zirconia, which still was tetragonal structure. The specific bonding property of interface still remained to be analyzed further to determine.

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An Efficient and Novel Ammonia Sensor Based on Polypyrrole/Tin Oxide/MWCNT Nanocomposite

Asian Journal of Chemistry ◽

10.14233/ajchem.2020.22648 ◽

2020 ◽

Vol 32 (6) ◽

pp. 1505-1510

Author(s):

Ahmad Husain ◽

Mohd Urooj Shariq ◽

Anees Ahmad

Keyword(s):

Electron Microscopy ◽

Tin Oxide ◽

Charge Carriers ◽

Morphological Properties ◽

X Ray Diffraction ◽

Ammonia Sensing ◽

Transmission Electron ◽

Ft Ir ◽

Ft Ir Spectroscopy

In present study, the synthesis and characterization of a novel polypyrrole (PPy)/tin oxide (SnO2)/MWCNT nanocomposite along with pristine polypyrrole is reported. These materials have been studied for their structural and morphological properties by FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. PPy/SnO2/MWCNT nanocomposite has been converted into a pellet-shaped sensor, and its ammonia sensing studies were carried out by calculating the variation in the DC electrical conductivity at different concentration of ammonia ranging from 10 to 1500 ppm. The sensing response of the sensor was determined at 1500, 1000, 500, 200, 100 and 10 ppm and found to be 70.4, 66.1, 62.2, 55.4, 50.8 and 39.7%, respectively The sensor showed a complete reversibility at lower concentrations along with excellent selectivity and stability. Finally, a sensing mechanism was also proposed involving polarons (charge carriers) of polypyrrole and lone pairs of ammonia molecules

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Preparation of Modified Chitosan Microsphere-Supported Copper Catalysts for the Borylation of α,β-Unsaturated Compounds

Polymers ◽

10.3390/polym11091417 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1417 ◽

Cited By ~ 1

Author(s):

Wang ◽

Xiao ◽

Huang ◽

Zheng ◽

Luo ◽

...

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Copper Catalysts ◽

Reduction Reaction ◽

X Ray ◽

Modified Chitosan ◽

Transmission Electron ◽

Ft Ir ◽

Repeated Use ◽

Supported Copper Catalysts

Chitosan microspheres modified by 2-pyridinecarboxaldehyde were prepared and used in the construction of a heterogeneous catalyst loaded with nano-Cu prepared by a reduction reaction. The chemical structure of the catalyst was investigated by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). Under mild conditions, such as no ligand at room temperature, the catalyst was successfully applied to catalyze the borylation of α,β-unsaturated receptors in a water-methanol medium, yielding 17%–100% of the corresponding -hydroxy product. Even after repeated use five times, the catalyst still exhibited excellent catalytic activity.

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Direct UHV-TEM Observation of Palladium Clusters on a Silicon Surface

Microscopy and Microanalysis ◽

10.1017/s143192760404022x ◽

2004 ◽

Vol 10 (1) ◽

pp. 134-138 ◽

Cited By ~ 2

Author(s):

Masaki Takeguchi ◽

Kazutaka Mitsuishi ◽

Miyoko Tanaka ◽

Kazuo Furuya

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Surface Layer ◽

Silicon Surface ◽

Lattice Structure ◽

Plan View ◽

Palladium Clusters ◽

Transmission Electron ◽

Pd Clusters

About 1 monolayer of palladium was deposited onto a silicon (111) 7 × 7 surface at a temperature of about 550 K inside an ultrahigh vacuum transmission electron microscope, resulting in formation of Pd2Si nanoislands and a 1 × 1 surface layer. Pd clusters created from an excess of Pd atoms on the 1 × 1 surface layer were directly observed byin situplan view high-resolution transmission electron microscopy. When an objective aperture was introduced so that electron diffractions less than 0.20 nm were filtered out, the lattice structure of the 1 × 1 surface with 0.33 nm spacing and the Pd clusters with a trimer shape were visualized. It was found that image contrast of the 1 × 1 lattice on the specific height terraces disappeared, and thereby an atomic structure of the Pd clusters was clearly observed. The appearance and disappearance of the 1 × 1 lattice was explained by the effect of the kinematical diffraction. It was identified that a Pd cluster was composed of three Pd atoms without a centered Si atom, which is consistent with the model proposed previously. The feature of the Pd clusters stuck at the surface step was also described.

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