scholarly journals Glycerol Valorization over ZrO2-Supported Copper Nanoparticles Catalysts Prepared by Chemical Reduction Method

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1040
Author(s):  
Juan Garcés ◽  
Ramón Arrué ◽  
Néstor Novoa ◽  
Andreia F. Peixoto ◽  
Ricardo J. Chimentão
Keyword(s):  
Copper Nanoparticles ◽  
Reduction Method ◽  
Chemical Reduction ◽  
X Ray Diffraction ◽  
Chemical Reduction Method ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Region I ◽  
Temperature Programmed

Copper nanoparticles (NPs) and ZrO2-supported copper NPs (Cu NPs/ZrO2) were synthesized via a chemical reduction method applying different pH (4, 7 and 9) and evaluated in a glycerol dehydration reaction. Copper NPs were characterized with transmission electron microscopy (TEM) and UV–vis spectroscopy. Transmission electron microcopy (TEM) results revealed a homogeneous distribution of copper NPs. A hypsochromic shift was identified with UV–vis spectroscopy as the pH of the synthesis increased from pH = 4 to pH = 9. Zirconia-supported copper NPs catalysts were characterized using N2 physisorption, X-ray diffraction (XRD), TEM, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), temperature-programmed desorption of ammonia (NH3-TPD) and N2O chemisorption. The presence of ZrO2 in the chemical reduction method confirmed the dispersion of the copper nanoparticles. X-ray diffraction indicated only the presence of tetragonal zirconia patterns in the catalysts. XPS identified the Cu/Zr surface atomic ratio of the catalysts. TPR patterns showed two main peaks for the Cu NPS/ZrO2 pH = 9 catalyst; the first peak between 125 and 180 °C (region I) was ascribed to more dispersed copper species, and the second one between 180 and 250 °C (region II) was assigned to bulk CuO. The catalysts prepared at pH = 4 and pH = 7 only revealed reduction at lower temperatures (region I). Copper dispersion was determined by N2O chemisorption. With NH3-TPD it was found that Cu NPs/ZrO2 pH = 9 exhibited the highest total quantity of acidic sites and the highest apparent kinetic constant, with a value of 0.004 min−1. The different pH applied to the synthesis media of the copper nanoparticles determined the resultant copper dispersion on the ZrO2 support, providing active domains for glycerol conversion.

scholarly journals A study concerning the pretreatment of CNTs and its influence on the performance of NIB/CNTs amorphous catalyst

2006 ◽  
Vol 71 (11) ◽  
pp. 1153-1160 ◽  
Author(s):  
Chang Hu-Yuan ◽  
Feng Li ◽  
Li. Hua ◽  
Bin Zhang
Keyword(s):  
Selective Hydrogenation ◽  
Inductively Coupled Plasma ◽  
Acid Treatment ◽  
Chemical Reduction ◽  
X Ray Diffraction ◽  
Chemical Reduction Method ◽  
X Ray ◽  
Inductively Coupled ◽  
Selective Hydrogenation Of Acetylene ◽  
Transmission Electron

As prepared carbon nanotubes were pretreated with nitric acid (CNTs-HNO3) or ammonia (CNTs-NH3). Fourier transform infrared spectroscopy (FTIR) measurements showed that the surface of the nanotubes was functionalized with carboxylic and hydroxyl functional groups after the acid treatment and that basic groups containing nitrogen, such as N-H and C-N, were introduced to the surface of the nanotubes after the ammonia treatment. X-Ray diffraction analysis implied that the nickel residue in the CNTs was effectively removed by acid treatment. However, the nickel residue was only partially eliminated by ammonia pretreatment. NiB amorphous catalysts supported on CNTs-HNO3 and CNTs-NH3 were prepared by the impregnation-chemical reduction method and characterized by transmission electron microscopy (TEM), as well as inductively coupled plasma (ICP) spectroscopy and studied in the selective hydrogenation of acetylene. TEM measurements showed that a high density NiB particles of about 9 nm were homogeneously dispersed on the CNTs-NH3. However, NiB particles (13-23 nm)with amean size of 16 nm were scattered on the CNTs-HNO3.As a result, the activity and selectivity of NiB/CNTs-NH3 were higher than those of NiB/CNTs-HNO3 in the selective hydrogenation of acetylene.

Facile synthesis of water-soluble graphene-based composite: Non-covalently functionalized with chitosan-ionic liquid conjugation

2016 ◽  
Vol 09 (03) ◽  
pp. 1650045 ◽  
Author(s):  
Pei-Ying Li ◽  
Kai-Yu Cheng ◽  
Xiu-Cheng Zheng ◽  
Pu Liu ◽  
Xiu-Juan Xu
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquid ◽  
Chemical Reduction ◽  
Water Soluble ◽  
X Ray Diffraction ◽  
Facile Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Text Interaction

Chitosan-ionic liquid conjugation (CILC), which was prepared through the reaction of 1-(4-bromobutyl)-3-methylimidazolium bromide (BBMIB) with chitosan, was firstly used to prepare functionalized graphene composite via the chemical reduction of graphene oxide (GO). The obtained water soluble graphene-based composite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), ultraviolet-visible (UV–Vis) spectroscopy and so on. CILC-RGO showed excellent dispersion stability in water at the concentration of 2.0 mg/mL, which was stable for several months without any precipitate. This may be ascribed to the electrostatic attraction and [Formula: see text]–[Formula: see text] interaction between CILC and graphene.

The Synthesis and Characterization of Oxide Free Tin Nanoparticles

2014 ◽  
Vol 670-671 ◽  
pp. 26-29
Author(s):  
Zhi Long Pan ◽  
Shi Liang Ao ◽  
Jian Ping Jia
Keyword(s):  
Reduction Method ◽  
Chemical Reduction ◽  
Thermal Characterization ◽  
X Ray Diffraction ◽  
Chemical Reduction Method ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Xrd Study ◽  
Tin Nanoparticles

Oxide free Tin nanoparticles were synthesized from a chemical reduction method. Their morphological and thermal characterizations were studied in this paper. The X-ray diffraction (XRD) study showed that no oxides of Tin nanoparticles were formed. The thermal characterization by differential scanning calorimetry (DSC) exhibited the size dependency of the melting points. The melting point was as low as 202.16°C.

Preparation of Fe3O4-Coated Microsilica Composites via Chemical Reduction Method

2013 ◽  
Vol 750-752 ◽  
pp. 1071-1074
Author(s):  
Hui Xia Feng ◽  
Bai Yi Chen ◽  
De Yi Zhang ◽  
Jian Qiang Zhang ◽  
He Ming Luo
Keyword(s):  
Electron Microscope ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Vibrating Sample Magnetometer ◽  
Chemical Reduction Method ◽  
Magnetic Composites ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Novel Method

Fe3O4-coated microsilica composites were synthesized by a novel method. The struction like precursor Fe3O4 nanoparticles as the shell and microsillica as the core for the composite has been prepared by chemical reduction method. The Fe3O4-coated microsilica composite presents a saturation magnetization value of 38.03 emu/g, which is sufficient to complete magnetic separation. The synthesized magnetic composites are characterized by X-ray diffractometer (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The results indicated that Fe3O4 nanoparticles successfully coated on microsilica.

Fast and Simple Fabrication of RGO/Ag Nanocomposite with Homogenous Dispersion

2013 ◽  
Vol 328 ◽  
pp. 674-678
Author(s):  
Xiao Juan Jiang ◽  
Guo Qiang Luo ◽  
Mei Juan Li ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Transmission Electron Microscope ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Chemical Reduction Method ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

The RGO/Ag nanocomposite with a homogeneous dispersion of Ag on the surface of RGO has been successfully prepared via situ chemical reduction method using DMF (dimethylformamide) as solvent and reducing agent. The RGO/Ag nanocomposite was characterized by X-ray diffractometer (XRD), Fourier transform-infrared (FTIR) spectra, Fieldemission scanning electron microscope (FESEM) and transmission electron microscope (TEM). It is suggested that in the presence of the PVP (polyvinylpyrrolidone), the electrostatic attraction of Ag+ions with negative GO sheets lead to the decoration of Ag nanoparticles on the surface of RGO sheets in RGO/Ag nanocomposite.

scholarly journals Core-shell SiO2/Ag composite spheres: synthesis, characterization and photocatalytic properties

2016 ◽  
Vol 34 (4) ◽  
pp. 806-810 ◽  
Author(s):  
Zhi Gang Wu ◽  
Yan Rong Jia ◽  
Jian Wang ◽  
Yang Guo ◽  
Jian Feng Gao
Keyword(s):  
Room Temperature ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Photocatalytic Properties ◽  
Core Shell ◽  
Chemical Reduction Method ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Photocatalytic Activities ◽  
Degradation Of Methyl Orange

AbstractCore-shell SiO2/Ag composite spheres with dense, complete and nanoscaled silver shell were prepared by using a novel facile chemical reduction method without surface modification of silica at room temperature. The core-shell composites were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy and energy dispersive X-ray spectroscopy (EDX). The photocatalytic properties towards the degradation of methyl orange (Mo) of the prepared SiO2/Ag composites were also tested. The studies showed that the surface of SiO2 microspheres was homogeneously and completely covered by Ag nanoparticles and the composite exhibited excellent photocatalytic activities. The possible reaction mechanisms for the formation of the silica-silver core-shell spheres were also discussed in this paper.

Formation of Platinum Nanodendrites Embedded Organic Insulator for Memory Application

2014 ◽  
Vol 1024 ◽  
pp. 44-47 ◽  
Author(s):  
Nur Syafinaz Ridhuan ◽  
Nabil Iman Muzzafaruddin ◽  
Abdul Razak Khairunisak ◽  
K.C. Aw
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Chemical Reduction Method ◽  
Growth Duration ◽  
X Ray ◽  
Transmission Electron ◽  
Average Size ◽  
Memory Characteristics

This work describes the formation of platinum nanodendrites (PtNDs) using the chemical reduction method. The PtNDs were formed with varying concentration of K2PtCl4 precursor (5-20 mM) and growth duration (8-16 min). The optimum concentration of K2PtCl4 was 15 mM whereby high crystalline nanodendrites with an average size of 118 nm were produced. Aggregation of nanodendrites occurred when the growth duration was prolonged to more than 12 minutes. The morphology and size of PtNDs were characterized by using a transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM) and X-ray diffractometer (XRD). Additionally, the memory characteristics of PtNDs embedded in polymethylsilsesquioxanes (PMSSQ)/Si with gold electrodes were studied in this work. PtNDs played a role as charge-trapped sites and showed good memory effect when embedded in PMSSQ. Optimum memory properties of PMSSQ-embedded PtNDs were obtained for PtNDs synthesized with 15 mM K2PtCl4 concentration at 12 min of growth duration with 170 electrons trapped per PtNDs and Vth of 2.8 V.

scholarly journals FusariumAntifungal Activities of Copper Nanoparticles Synthesized by a Chemical Reduction Method

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Pham Van Viet ◽  
Hai Thi Nguyen ◽  
Thi Minh Cao ◽  
Le Van Hieu
Keyword(s):  
Copper Nanoparticles ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Fungal Growth ◽  
Spherical Shape ◽  
Xrd Analysis ◽  
Chemical Reduction Method ◽  
Transmission Electron ◽  
Ft Ir ◽  
Average Size

We report on the process of synthesizing copper nanoparticles (Cu Nps) for a short reactive time by chemical reduction method with a support of CTAB reductive agent. Their properties were determined by ultraviolet-visible (UV-Vis) absorption spectrum, the X-ray (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR), and Transmission Electron Microscopy (TEM) images. The antifungal activity of Cu Nps was evaluated by testing againstFusariumsp. The Cu Nps were obtained with the average size in the range of 20–50 nm having spherical shape. The survey shows that when Cu Nps were used at 450 ppm concentration in 9-day incubation, 93.98% of fungal growth was inhibited.

scholarly journals Synthesis of Colloidal Ruthenium Nanocatalyst by Chemical Reduction Method

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
R. G. Patharkar ◽  
S. U. Nandanwar ◽  
M. Chakraborty
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Chemical Reduction ◽  
Sodium Dodecyl ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Chemical Reduction Method ◽  
X Ray ◽  
Ru Nanoparticles ◽  
Transmission Electron

Colloidal ruthenium nanoparticles were prepared by chemical reduction of ruthenium trichloride (RuCl3) using sodium borohydrate (NaBH4) as reducing agent and sodium dodecyl sulfate (SDS) as a stabilizer. Size and size distribution of synthesized colloidal Ru nanoparticles were studied by varying different parameters such as molar ratio (MR) of SDS/RuCl3, NaBH4/RuCl3, effects of different stabilizers, and reducing agents. Prepared nanoparticles were characterized by transmission electron microscope (TEM) and dynamic light scattering (DLS). Stability of colloidal nanoparticles was detected by Turbiscan. Stable Ru nanoparticles were dispersed onγ-Al2O3to prepare Ru/γ-Al2O3catalyst. This catalyst was characterized by X-ray Diffraction (XRD) and transmission electron microscope (TEM).

Preparation and Characterization of Pt/Superfine Mesocarbon Microbead Powers Electrocatalysts

2005 ◽  
Vol 3 (3) ◽  
pp. 358-360 ◽  
Author(s):  
Jia Rong-Li ◽  
Wang Cheng-Yang ◽  
Zhu Bin
Keyword(s):  
Reduction Method ◽  
Direct Methanol Fuel Cells ◽  
Electrochemical Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Platinum Particles ◽  
Platinum Electrocatalyst ◽  
Direct Methanol

Superfine mesocarbon microbead powders (SFMCMBs) as the new supports for platinum electrocatalysts were first investigated. The Pt∕SFMCMB electrocatalysts were prepared by an impregnation-reduction method, with hexachloroplatinic acid as the platinum precursor and formaldehyde as the reducing agent. The catalysts were characterized with x-ray diffraction (XRD), field emission gun transmission electron microscope (TEM), and electrochemical analysis. TEM photos showed the platinum particles were dispersed uniformly on the surface of SFMCMBs and there existed a little aggregation of platinum particles in the Pt∕SFMCMB catalysts. The TEM photos showed the existence of the platinum on the supports where the average platinum particle size were 4-6nm. The electrochemical analysis proved that SFMCMBs are excellent candidates to be used as the support of platinum electrocatalyst for methanol electrochemical oxidation as the potential catalyst candidate for direct methanol fuel cells (DMFCs).

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