scholarly journals Mechanochemically Synthesized Supported Magnetic Fe-Nanoparticles as Catalysts for Efficient Vanillin Production

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 290 ◽  
Author(s):  
María Dolores Márquez‐Medina ◽  
Daily Rodríguez-Padrón ◽  
Alina M. Balu ◽  
Antonio A. Romero ◽  
Mario J. Muñoz-Batista ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Catalytic Properties ◽  
Single Step ◽  
High Catalytic Activity ◽  
Vanillyl Alcohol ◽  
X Ray Diffraction ◽  
Key Factors ◽  
X Ray ◽  
Oxide Precursor ◽  
Transmission Electron

Magnetically separable nanocatalysts were synthesized by incorporating ironnanoparticles on a mesoporous aluminosilicate (Al-SBA-15) through a mechanochemical grindingpathway in a single step. Noticeably, magnetic features were achieved by employing biomass wasteas a carbon source, which additionally may confer high oxygen functionalities to the resultingmaterial. The resulting catalysts were characterized using X-ray diffraction, X-ray photoelectronspectroscopy, transmission electron microscopy, scanning electron microscopy, porosimetry, andmagnetic susceptibility. The magnetic nanocatalysts were tested in the selective oxidative cleavagereaction of isoeugenol and vanillyl alcohol to vanillin. As a result, the magnetic nanocatalystsdemonstrated high catalytic activity, chemical stability, and enormous separation/reusabilityqualities. The origin of catalytic properties and its relationship with the iron oxide precursor wereanalyzed in terms of the chemical, morphological, and structural properties of the samples. Suchanalysis allows, thus, to highlight the superficial concentration of the iron entities and the interactionwith Al as key factors to obtain a good catalytic response.

Growth of nanocrystals and thin films at the water–oil interface

2010 ◽  
Vol 368 (1927) ◽  
pp. 4313-4330 ◽  
Author(s):  
G. L. Stansfield ◽  
P. V. Vanitha ◽  
H. M. Johnston ◽  
D. Fan ◽  
H. AlQahtani ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Emission Spectroscopy ◽  
Single Step ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Transmission Electron ◽  
Solid Substrates ◽  
Absorption And Emission Spectroscopy

The use of the water–oil interface provides significant advantages in the synthesis of inorganic nanostructures. Employing the water–toluene interface, luminescent CdS nanocrystals have been obtained at a relatively modest temperature of 35 ° C. The diameters of the particulates can be varied between 1.0 and 5.0 nm. In addition, we have devised a new method for transferring thin films at the water–toluene interface onto solid substrates. Using this method, thin films consisting of Au and Ag nanocrystals spread over very large areas (square centimetres) are obtained in a single step. These films are directly usable as ingredients of functional devices. We show this by constructing a working amine sensor based on films of Au nanocrystals. The materials obtained have been characterized by X-ray diffraction, scanning and transmission electron microscopy, absorption and emission spectroscopy and charge transport measurements.

Synthesis of Ni-Mo-W Sulfide Nanorods as Catalyst for Hydrodesulfurization of Dibenzothiophene

2008 ◽  
Vol 8 (12) ◽  
pp. 6406-6413 ◽  
Author(s):  
F. Paraguay-Delgado ◽  
R. García-Alamilla ◽  
J. A. Lumbreras ◽  
E. Cizniega ◽  
G. Alonso-Núñez
Keyword(s):  
Electron Microscopy ◽  
Physical Adsorption ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Precursor ◽  
Transmission Electron ◽  
Adsorption Of Nitrogen ◽  
Diffraction Patterns ◽  
Scanning Electron

Two trimetallic sulfurs, MoWNiS and MoWSNi, were synthesized to be used as a catalyst in hydrodesulfurization reactions. The mixed oxide mesoporous nanostructured MoO3-WO3 with an Mo:W atomic ratio of 1:1 was used as the precursor. The first catalyst was prepared by impregnating nickel in the oxide precursor and then subsequent sulfiding with an H2S/H2 mix at 400 °C for 2 hours. The second catalyst was prepared by sulfiding the precursor and then impregnating the nickel, and finally reducing the material with a H2/N2 at 350 °C. In both catalysts the Mo:W:Ni atomic ratio was maintained at 1:1:0.5. The materials obtained were characterized by physical adsorption of nitrogen, X-ray diffraction, scanning electron microscopy, transmission electron microscopy. Furthermore, the materials obtained were evaluated by a dibenzothiophene hydrodesulfuration reaction. The diffraction patterns show that both materials are polycrystalline and mainly of MoS2 and WS2 phases.

scholarly journals On the kinetics of the hydrogen evolution reaction on Ni-MoOx composite catalysts in alkaline solutions

2012 ◽  
Vol 77 (2) ◽  
pp. 211-224 ◽  
Author(s):  
Borka Jovic ◽  
Uros Lacnjevac ◽  
Vladimir Jovic ◽  
Ljiljana Gajic-Krstajic ◽  
Nedeljko Krstajic
Keyword(s):  
Electron Microscopy ◽  
Constant Current ◽  
Catalyst Stability ◽  
Alkaline Solutions ◽  
High Catalytic Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composite Catalysts ◽  
Transmission Electron ◽  
Kinetics Of

MoO3 particles were co-deposited with Ni onto smooth or rough Ni supports from modified Watt?s baths of different compositions. Morphology and composition of the electrodeposits were characterized by means of cyclic voltammetry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The electrocatalytic activity of the composite catalysts for H2 evolution in alkaline solutions was determined by quasi-stationary polarization curves. Activity increases with MoOx content in the Ni deposit up to a limiting value. Composite Ni-MoOx catalyst performed high catalytic activity, similar to that of commercial Ni-RuO2 catalyst. Stability tests showed that Ni-MoOx codeposits are stable under condition of constant current and exhibit excellent tolerance to repeated short-circuiting.

scholarly journals A Colorimetric Assay for the Detection of Glucose and H2O2 Based on Cu-Ag/g-C3N4/ZIF Hybrids with Superior Peroxidase Mimetic Activity

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4432
Author(s):  
Quan Pan ◽  
Yuelin Kong ◽  
Kuan Chen ◽  
Mi Mao ◽  
Xiaohui Wan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Colorimetric Assay ◽  
X Ray Diffraction ◽  
Zeolitic Imidazolate Framework ◽  
X Ray ◽  
Transmission Electron ◽  
H2o2 Generation

In this work, we report the synthesis of Cu-Ag bimetallic nanopartiles and g-C3N4 nanosheets decorated on zeolitic imidazolate framework-8 (ZIF-8) to form a Cu-Ag/g-C3N4/ZIF hybrid. The hybrid was synthesized and characterized by Transmission electron microscopy (TEM), Fourier transformed infrared (FTIR), the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Cu-Ag/g-C3N4/ZIF hybrid has intrinsic peroxidaselike catalytic activity towards the oxidation of TMB in the presence of H2O2. The situ synthesis of Cu-Ag bimetallic nanopartiles on 2D support such as g-C3N4 nanosheets would significantly enhance the peroxidaselike catalytic properties of individual Cu-Ag bimetallic nanopartiles and the g-C3N4 nanosheets. After loading of Cu-Ag bimetallic nanopartiles and g-C3N4 nanosheets on the ZIF-8, the hybrids exhibited superior peroxidaselike catalytic activity and good recyclability. Then, this method was applied for detecting glucose in human serum, owing the significant potential for detection of metabolites with H2O2-generation reactions.

A Single-Step Synthesis of Rutile TiO2 Dendrite Crystal with Sonication

2011 ◽  
Vol 356-360 ◽  
pp. 399-402 ◽  
Author(s):  
Xi Kui Wang ◽  
Wei Lin Guo ◽  
Chen Wang
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Single Step ◽  
Sonochemical Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Crystalline Forms ◽  
Hydrolysis Of

A single-step sonochemical method to directly prepare rutile nanocrystal TiO2 has been developed. TiO2 nanaoparticles were synthesized by the hydrolysis of TiCl4 in the presence of water and ethanol under ultrasonic irradiationat 70 °C for 3 h. The crystalline forms and crystallite sizes of the produts were characterized by X-ray diffraction, transmission electron microscopy and thermogravimetry-differential thermal analysis. The TEM images showed the morphology of as-prapared TiO2 was pinnate in shape and the average sizes were ca. 4/12 nm (W/L). The columnar particles were linked together each other at the certain principle, forming the shape like dendrite crystal. The formation mechanism of the dendrite crystal nanocrystalline TiO2 was also discussed.

scholarly journals Green Synthesis of Iron Oxide-Palladium Nanocomposites by Pepper extract and Its Application in Removing of Colored Pollutants from Water

2017 ◽  
Vol 7 (3) ◽  
Author(s):  
Shahab Khaghani
Keyword(s):  
Electron Microscopy ◽  
Fe3o4 Nanoparticles ◽  
Catalytic Properties ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Ultraviolet Light Irradiation ◽  
Paramagnetic Behaviour ◽  
Catalytic Behaviour

Fe3O4 nanoparticles were synthesized in the presence of pepper extract as a capping agent via a hydrothermal method. Then palladium nanoparticles and Fe3O4-Pd nanocomposites were synthesized with the aid of pepper extract as a reducing agent. Vibrating Sample magnetometer illustrated that Fe3O4 nanoparticles have super paramagnetic behaviour. The photo catalytic behaviour of Fe3O4-Pd nanocomposites was investigated using the degradation of two azo dyes under ultraviolet light irradiation. The results show that nanocomposites have feasible magnetic and photo catalytic properties. The prepared products were characterized by X-ray diffraction pattern, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy.

SINGLE STEP SYNTHESIS OF HYDROPHOBIC AND HYDROPHILIC NANOPARTICLES VIA THERMAL DECOMPOSITION

2011 ◽  
Vol 10 (04n05) ◽  
pp. 943-947 ◽  
Author(s):  
DIPAK MAITY ◽  
JUN DING
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Decomposition ◽  
Single Step ◽  
Organometallic Complexes ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Here, we report single step synthesis of hydrophobic and hydrophilic Fe3O4 , ZnO , CoO and Y2O3:Eu nanoparticles via thermal decomposition of different organometallic complexes in oleylamine (OM) and tri(ethyleneglycol) (TREG) media, respectively. The crystal structure of the as-prepared nanoparticles is identified using X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Morphology of the nanoparticles is determined by transmission electron microscopy (TEM) while the magnetic properties are measured using vibrating sample magnetometer (VSM). Thermolysis of appropriate precursors in OM and TREG medium are very capable of producing the highly dispresed hydrophobic and hydrophilic nanoparticles with diverse morphologies.

Fabrication of 3D hierarchical Fe2O3/SnO2 photoanode for enhanced photoelectrochemical performance

2022 ◽  
Author(s):  
Xing Zhang ◽  
Hao Chen ◽  
Wei Zhang ◽  
Lina Zhang ◽  
Xinyu Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocurrent Density ◽  
Annealing Process ◽  
High Catalytic Activity ◽  
X Ray Diffraction ◽  
Photoelectrochemical Performance ◽  
Hydrothermal Route ◽  
Hydrogen Electrode ◽  
X Ray ◽  
Transmission Electron

Abstract Exploring and fabricating a suitable photoanode with high catalytic activity is critical for enhancing photoelectrochemical (PEC) performance. Herein, a novel 3D hierarchical Fe2O3/SnO2 photoanode was fabricated by a hydrothermal route, combining with an annealing process. The morphology, crystal structure were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photon spectroscopy (XPS), and X-ray diffraction (XRD), respectively. The results reveal the successful preparation of Fe2O3 nanothorns on the surface of SnO2 nanosheets. The as-fabricated 3D Fe2O3/SnO2 photoanode yields obviously promoted PEC performance with a photocurrent density of approximate 5.85 mA cm-2, measured in a mixture of Na2S (0.25 M) and Na2SO3 (0.35 M) aqueous solution at 1.23 V (vs. reversible hydrogen electrode, RHE). This value of photocurrent is about 53 times higher than that of the bare SnO2 photoanode. The obvious improved PEC properties can be attributed to the 3D Fe2O3/SnO2 heterostructures that offer outstanding light harvesting ability as well as improved charge transport and separation. These results suggest that exploring a suitable 3D hierarchical photoanode is an effective approach to boost PEC performance.approach to boost PEC performance.

scholarly journals Green synthesis of stable Fe,Cu oxide nanocomposites from loquat leaf extracts for removal of Norfloxacin and Ciprofloxacin

2020 ◽  
Vol 81 (4) ◽  
pp. 694-708
Author(s):  
Qiujie Liu ◽  
Peili Ma ◽  
Penglei Liu ◽  
Hongping Li ◽  
Xiuli Han ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Single Step ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
Step Method ◽  
Leaf Extracts ◽  
X Ray ◽  
Transmission Electron ◽  
Equilibrium Data

Abstract Mass production of nanomaterials to remove pollutants from water still faces many challenges, mainly due to the complexity of the synthesis methods involved and the use of dangerous reagents. The green method of preparation of nanomaterials from plants can effectively solve these problems. Fe,Cu oxide nanocomposites (Fe-Cu-NCs) were synthesized by a green and single-step method using loquat leaf extracts, and were used as an adsorbent for removal of Norfloxacin (NOR) and Ciprofloxacin (CIP) from aqueous solution. The synthesized adsorbent showed excellent adsorption properties for NOR and CIP. The experimental equilibrium data fitted the Redlich-Peterson and Koble-Corrigan models well and the maximum adsorption capacities of Fe-Cu-NCs calculated by the Langmuir model for NOR and CIP were 1.182 mmol/g and 1.103 mmol/g, respectively, at 293 K. Additionally, the morphologies and properties of Fe-Cu-NCs were characterized by transmission electron microscopy (TEM), scanning electron microscopy X-ray energy-dispersive spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis and the adsorption mechanism of NOR and CIP onto Fe-Cu-NCs was discussed. Thermodynamic parameters revealed that the adsorption process was spontaneous and endothermic. This study indicated that Fe-Cu-NCs are a potential adsorbent and provide a simple and convenient strategy for the purification of antibiotics-laden wastewater.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

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