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.

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 Catalytic Properties of Alumina-Supported Ruthenium, Platinum, and Cobalt Nanoparticles towards the Oxidation of Cyclohexane to Cyclohexanol and Cyclohexanone

2018 ◽  
Vol 13 (1) ◽  
pp. 24
Author(s):  
Ilhem Rekkab-Hammoumraoui ◽  
Abderrahim Choukchou-Braham
Keyword(s):  
Inductively Coupled Plasma ◽  
Catalytic Properties ◽  
Optical Emission ◽  
Cobalt Nanoparticles ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Transmission Electron

A series of metal-loaded (Ru, Pt, Co) alumina catalysts were evaluated for the catalytic oxidation of cyclohexane using tertbutylhydroperoxide (TBHP) as oxidant and acetonitrile or acetic acid as solvent. These materials were prepared by the impregnation method and then characterized by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), H2 chemisorption, Fourier Transformed Infrared Spectroscopy (FTIR), High-Resolution Transmission Electron Microscopy (HRTEM), and X-ray Diffraction (XRD). All the prepared materials acted as efficient catalysts. Among them, Ru/Al2O3 was found to have the best catalytic activity with enhanced cyclohexane conversion of 36 %, selectivity to cyclohexanol and cyclohexanone of 96 % (57.6 mmol), and cyclohexane turnover frequency (TOF) of 288 h-1. Copyright © 2018 BCREC Group. All rights reservedReceived: 26th May 2017; Revised: 17th July 2017; Accepted: 18th July 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Rekkab-Hammoumraoui, I., Choukchou-Braham, A. (2018). Catalytic Properties of Alumina-Supported Ruthenium, Platinum, and Cobalt Nanoparticles towards the Oxidation of Cyclohexane to Cyclohexanol and Cyclohexanone. Bulletin of Chemical Reaction Engineering & Catalysis, 13(1): 24-36 (doi:10.9767/bcrec.13.1.1226.24-35) 

Preparation of Nanosized RuB with Lower Ru Content Supported on Al2O3 and its Catalytic Activity

2012 ◽  
Vol 557-559 ◽  
pp. 1467-1470
Author(s):  
Sheng Xian Xu ◽  
Feng Yi Li
Keyword(s):  
Catalytic Activity ◽  
Amorphous Alloy ◽  
Inductively Coupled Plasma ◽  
Chemical Reduction ◽  
Benzene Hydrogenation ◽  
Transmission Electron Micrograph ◽  
X Ray Diffraction ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Loading Amount

The nanosized RuB amorphous alloys with three different ruthenium contents supported on Al2O3 were prepared by means of impregnation, following the chemical reduction with KBH4 solution. The gas-phase benzene hydrogenation was used as a probe reaction to evaluate the catalytic activity of the prepared catalysts. The catalysts were characterized by BET, inductively coupled plasma (ICP), X-ray diffraction (XRD), and transmission electron micrograph (TEM). The experiment results show that the catalytic activity of the three amorphous alloy catalysts goes up first with the increasing of temperature and has a maximum at 443K; when the Ru loading amount is 0.24 %(wt.%) of the catalyst, which is very few, the conversion of benzene on RuB/Al2O3 amorphous alloy catalyst can reach to 99.50% at 443K.

PREPARATION AND ELECTROCHEMICAL PROPERTIES OF NANOSTRUCTURED Li0.8CoO2

2006 ◽  
Vol 05 (02n03) ◽  
pp. 285-290 ◽  
Author(s):  
YONGHUA LENG ◽  
XINGGUO LI ◽  
HUAQUAN YANG ◽  
HENGHUI ZHOU
Keyword(s):  
Electrochemical Properties ◽  
Inductively Coupled Plasma ◽  
Sol Gel ◽  
Open Circuit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Grinding Method ◽  
Transmission Electron ◽  
Lower Discharge

Submicron Li 0.8 CoO 2 particles were prepared by sol–gel method, and then ball-mill grinding method was adopted to make nanosized Li 0.8 CoO 2 powders. The two kinds of powders were then examined by X-ray diffraction (XRD), ICP (inductively coupled plasma), the multi-point BET (Brunauer, Emmett and Teller) and transmission electron micrographs (TEM). It appeared that the Li 0.8 CoO 2 nanoparticles exhibited quite different electrochemical properties, such as higher open-circuit voltage and lower discharge capacity, compared to submicron Li 0.8 CoO 2 particles.

The nature and origin of non-marine 10 Å clay from the Late Eocene and Early Oligocene of the Isle of Wight (Hampshire Basin), UK

Clay Minerals ◽  
2001 ◽  
Vol 36 (3) ◽  
pp. 447-464 ◽  
Author(s):  
J. M. Huggett ◽  
A. S. Gale ◽  
N. Clauer
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
Late Eocene ◽  
X Ray Diffraction ◽  
Wetting And Drying ◽  
Wet Chemistry ◽  
X Ray ◽  
Inductively Coupled ◽  
Early Oligocene ◽  
Transmission Electron

AbstractVariegated palaeosols, which formed from weathering of clays, silts and brackish to freshwater limestones, are present in the Late Eocene–Early Oligocene Solent Group of the Hampshire Basin, southern UK. The composition and origin of the clay in three segments of the lower part of the Solent Group have been investigated by X-ray diffraction, microprobe analysis, inductively coupled plasma-mas spectrometry, K/Ar dating, high resolution scanning electron microscopy, analytical transmission electron microscopy and wet chemistry. The detrital clay mineral suite is dominated by illite and smectite with minor kaolinite and chlorite. Seasonal wetting and drying in gley soils has resulted in replacement of smectite by Fe-rich, or illite-rich illitesmectite. Illite has also formed with gypsum and calcite in ephemeral hypersaline alkaline lakes that periodically dried out. This illite may have precipitated directly from solution. X-ray diffraction data and probe analyses indicate that the neoformed illite is Fe-rich. The K and Fe for the illitization are thought to be derived from weathered glauconite reworked from the underlying Bracklesham Group and Barton Beds.

scholarly journals Ag nanoparticles immobilized on new mesoporous triazine-based carbon (MTC) as green and recoverable catalyst for reduction of nitroaromatic in aqueous media

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Narges Vahedi-Notash ◽  
Majid M. Heravi ◽  
Ali Alhampour ◽  
Pourya Mohammadi
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
Aqueous Media ◽  
Catalytic Efficiency ◽  
Active Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Recoverable Catalyst

Abstract In this research, we reported an effective method for the synthesis of a new mesoporous triazine-based carbon (MTC) substrate and its application as the green and recoverable catalyst in the synthesis of organic compounds. The porous carbon acted as a substrate for silver active species after its surface modification by chloroacetonitrile (Ag@MTC). The Ag@MTC nanocatalyst was characterized by several techniques namely, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy with energy dispersive spectroscopy, X-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller surface area analysis, and inductively coupled plasma. The Ag@MTC catalyst was applied for the reduction of nitroaromatic compounds in aqueous media by using NaBH4 (reducing agent) at room temperature. This nanocatalyst can be readily recovered and recycled for at least nine runs without a notable decrease in its efficiency. Catalytic efficiency studies exhibited that Ag@MTC nanocatalyst had good activity towards reduction reactions.

Synthesis and Characterization of Fe2+-CTS/CA-CNTs Composite and its Magnetic Properties

2013 ◽  
Vol 680 ◽  
pp. 49-53
Author(s):  
Chang Yu ◽  
Xu Zhang ◽  
Kan He ◽  
Yue Liu ◽  
Jie Shan Qiu
Keyword(s):  
Electron Microscopy ◽  
Magnetic Properties ◽  
Inductively Coupled Plasma ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Superparamagnetic State

A novel biocompatible Fe2+-chitosan (CTS)/citric acid modified carbon nanotube (CA-CNTs) composite (Fe2+-CTS/CA-CNTs) has been successfully synthesized by covalent bonding and crosslinking chemistry, followed by the reduction. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis spectrum, X-ray diffraction (XRD), inductively coupled plasma (ICP), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM) techniques. The results show that the CTS has been successfully grafted to the CA-CNTs carrier and Fe2+ ions are absorbed on the CTS by coordination bond mode. It was found that the Fe2+-CTS/CA-CNTs composite shows good magnetic properties with a low ratio of remanence to saturation magnetization and is in a superparamagnetic state at room temperature. It is believed that the Fe2+-CTS/CA-CNTs composite will be potential for application in MRI.

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).

scholarly journals Green Synthesis of CuInS2/ZnS Nanocrystals with High Photoluminescence and Stability

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Min Fu ◽  
Weiling Luan ◽  
Shan-Tung Tu ◽  
Leslaw Mleczko
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Shell Growth ◽  
Optical Emission ◽  
Growth Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Zns Nanocrystals

Highly photoluminescent core/shell CuInS2/ZnS (CIS/ZnS) nanocrystals were synthesized. Zinc acetate and dodecanethiol in octadecene solvent were used for shell growth. The structure and composition of QDs were investigated with inductively coupled plasma-optical emission spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The crystal phase of CIS was tetragonal chalcopyrite. Based on X-ray diffraction analysis, it has been concluded that the growth of the ZnS shell did not affect the phase structure of CuInS2(CIS). Photoluminescence (PL) quantum yield (QY) of CIS increased to 80% after epitaxial growth of ZnS, and the PL emission wavelength can be feasibly tuned to be in the range of 560–710 nm by adjusting shell growth time. The superb photostability with high PL QY of CIS/ZnS nanocrystals is ascribed to the gradient of the chemical composition that has been formed between the core and the shell.

Facile Synthesis of Basic Magnesium Carbonate with Different Morphology

2012 ◽  
Vol 554-556 ◽  
pp. 575-579 ◽  
Author(s):  
Yun Chuan Yang ◽  
Hong Hao Yu ◽  
Xin Ying Wang
Keyword(s):  
Electron Microscopy ◽  
Inductively Coupled Plasma ◽  
Atomic Emission ◽  
Magnesium Carbonate ◽  
X Ray Diffraction ◽  
Plasma Atomic Emission ◽  
Facile Synthesis ◽  
X Ray ◽  
Inductively Coupled ◽  
Transmission Electron

The preparation of different morphological basic magnesium carbonate particles with hollow rod-like, hull of peanut and leaf from the pyrogenation of magnesium carbonate trihydrate were described. The morphology, crystal phase and purity of basic magnesium carbonate were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction (XRD) and inductively coupled plasma atomic emission spectrometer (ICP-AES). The results indicated that the formation of three morphological basic magnesium carbonates were obtained via platelike particles of magnesium carbonate trihydrate under certain conditions where the temperature and stirring rate were properly controlled. The length of the hollow rod means up to 6～7µm, and its diameter means up to 1～2µm.

Sign in / Sign up

Export Citation Format

Share Document