Carbon-Supported Nickel Nanoparticles from a Wood Sample of the Tree Sebertia acuminata Pierre ex. Baillon

2010 ◽  
Vol 63 (5) ◽  
pp. 830 ◽  
Author(s):  
Martin Lerch ◽  
Thorsten Ressler ◽  
Frank Krumeich ◽  
Jean-Pierre Cosson ◽  
Edouard Hnawia ◽  
...  

A wood sample of the nickel hyperaccumulator tree Sebertia acuminata Pierre ex. Baillon was pyrolyzed in an inert atmosphere to produce a charcoal-like material containing nanoparticulate nickel. Its overall nickel content was determined to be ~7 wt-% by wet chemical analysis (acid digestion, inductively coupled plasma optical emission spectroscopy). Depending on the conditions of pyrolysis (5 h at 800°C; or 5 h at 800°C followed by 7 h at 900°C), the average crystallite sizes were ~7 and 42 nm, respectively, as determined by X-ray powder diffraction (XRD) and electron microscopy (scanning, scanning transmission, and transmission). Furthermore, high resolution transmission electron microscopy images reveal that the Ni particles are, in some cases, encapsulated with graphitic carbon layers of varying thickness. Scanning electron microscopy results indicate for the most part, a preservation of the wood framework and a remarkably uniform distribution of the nickel nanoparticles in the vessels of the xylem. XRD and X-ray absorption fine structure analysis reveal the presence of NiO besides Ni.

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 490
Author(s):  
Rudaviro Garidzirai ◽  
Phillimon Modisha ◽  
Innocent Shuro ◽  
Jacobus Visagie ◽  
Pieter van Helden ◽  
...  

The effects of Mg and Zn dopants on the catalytic performance of Pt/Al2O3 catalyst were investigated for dehydrogenation of perhydrodibenzyltoluene (H18-DBT) as a liquid organic hydrogen carrier. Al2O3 supports were modified with Mg and Zn to produce Mg-Al2O3 and Zn-Al2O3 with a target loading of 3.8 wt.% for dopants. The modified supports were impregnated with chloroplatinic acid solution to produce the catalysts Pt/Al2O3, Pt/Mg-Al2O3 and Pt/Zn-Al2O3 of 0.5 wt.% Pt loading. Thereafter, the catalysts were characterised using inductively coupled plasma- optical emission spectrometry, scanning electron microscopy-energy dispersive X-ray spectroscopy, hydrogen temperature-programmed reduction, carbon-monoxide pulse chemisorption, ammonia temperature-programmed desorption, X-ray diffraction and transmission electron microscopy. The dehydrogenation experiments were performed using a horizontal plug flow reactor system and the catalyst time-on-stream was 22 h. Pt/Mg-Al2O3 showed the highest average hydrogen flowrate of 29 nL/h, while an average of 27 nL/h was obtained for both Pt/Al2O3 and Pt/Zn-Al2O3. This has resulted in a hydrogen yield of 80% for Pt/Mg-Al2O3, 71% for Pt/Zn-Al2O3 and 73% for Pt/Al2O3. In addition, the conversion of H18-DBT ranges from 99% to 92%, Pt 97–90% and 96–90% for Pt/Mg-Al2O3, Pt/Zn-Al2O3 and Pt/Al2O3, respectively. Following the latter catalyst order, the selectivity to dibenzyltoluene (H0-DBT) ranges from 78% to 57%, 75–51% and 71–45%. Therefore, Pt/Mg-Al2O3 showed improved catalytic performance towards dehydrogenation of H18-DBT.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mansoureh Daraie ◽  
Majid M. Heravi ◽  
Yalda Rangraz ◽  
Zahra Besharati

AbstractA hybrid system was designed and synthesized through reacting modified halloysite (Hal-Cl) with Schiff base (DAB-PC) and applied as catalytic support for anchoring Pd NPs to afford Pd@Hal-DAB-PC catalyst. The resultant material was well identified by various analyses including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction patterns (XRD), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and inductively coupled plasma-optical emission spectrometry (ICP-OES) and revealed outstanding catalytic activity in the Sonogashira reaction in aqueous media. Also, This nanocatalyst was simply collected and recycled up to six runs with a slight drop in efficiency, indicating the durability of Pd@Hal-DAB-PC.


2018 ◽  
Vol 5 (6) ◽  
pp. 171884 ◽  
Author(s):  
Laura-Jayne A. Ellis ◽  
Anastasios G. Papadiamantis ◽  
Stefan Weigel ◽  
Eugenia Valsami-Jones

The reliable quantification of nanomaterials (NMs) in complex matrices such as food, cosmetics and biological and environmental compartments can be challenging due to interactions with matrix components and analytical equipment (vials and tubing). The resulting losses along the analytical process (sampling, extraction, clean-up, separation and detection) hamper the quantification of the target NMs in these matrices as well as the compatibility of results and meaningful interpretations in safety assessments. These issues can be overcome by the addition of known amounts of internal/recovery standards to the sample prior to analysis. These standards need to replicate the behaviour of target analytes in the analytical process, which is mainly defined by the surface properties. Moreover, they need to carry a tag that can be quantified independently of the target analyte. As inductively coupled plasma mass spectrometry is used for the identification and quantification of NMs, doping with isotopes, target analytes or with chemically related rare elements is a promising approach. We present the synthesis of a library of TiO 2 NMs doped with hafnium (Hf) and zirconium (Zr) (both low in environmental abundance). Zirconia NMs doped with Hf were also synthesized to complement the library. NMs were synthesized with morphological and size properties similar to commercially available TiO 2 . Characterization included: transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, Brunauer–Emmett–Teller total specific surface area analysis, cryofixation scanning electron microscopy, inductively coupled plasma optical emission spectroscopy and UV–visible spectrometry. The Ti : Hf and Ti : Zr ratios were verified and calculated using Rietveld refinement. The labelled NMs can serve as internal standards to track the extraction efficiency from complex matrices, and increase method robustness and traceability of characterization/quantification.


Chemija ◽  
2020 ◽  
Vol 31 (1) ◽  
Author(s):  
Jolita Jablonskienė ◽  
Dijana Šimkūnaitė ◽  
Jūratė Vaičiūnienė ◽  
Algirdas Selskis ◽  
Audrius Drabavičius ◽  
...  

MnO2/C nanocomposites have been prepared using a simple onestep microwave heating method by applying different concentrations of cationic surfactant – cetyl trimethylammonium bromide (CTAB). The morphology and composition of the prepared MnO2/C nanocomposites have been investigated using X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The electrochemical performance of the prepared nanocomposites has been analysed using cyclic voltammetry. It was found that a high specific capacitance (Cs) of 742 F g−1 at a scan rate of 10 mV s−1 in a 1 M Na2SO4 solution has been obtained for the MnO2/C nanocomposite that has the mass loading of 0.140 mg cm−2 and has been synthesized in the absence of CTAB. Meanwhile, the application of CTAB allowed the increase in the mass loading of MnO2 in the nanocomposites. In the presence of CTAB, the highest value of 654 F g−1 at a scan rate of 10 mV s−1 has been obtained for MnO2/C that has the mass loading of 0.570 mg cm−2. This result confirmed a good performance of the prepared MnO2/C nanocomposites as the electrode material for supercapacitors.


1981 ◽  
Vol 35 (2) ◽  
pp. 226-235 ◽  
Author(s):  
Robert L. Eklund

Remembering where we came from, points out author Alex Haley in Roots, helps us know who we are today. The roots of spectroscopy are closely intertwined with those of Bausch & Lomb-ARL, known to the industry for more than 45 years as Applied Research Laboratories. A member of Bausch & Lomb's Instrument Group, ARL today is a major multinational supplier of spectrochemical instruments in the optical emission, inductively coupled plasma (ICP), X-ray fluorescence and diffraction, microanalysis, and scanning electron microscopy fields. Its story begins with a graduate student's dream—which, unlike most dreams, came true.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Izabela Michalak ◽  
Krzysztof Marycz ◽  
Katarzyna Basińska ◽  
Katarzyna Chojnacka

The biomass ofVaucheria sessilisforms algal mats in many freshwaters. There is a need to find the method of algal biomass utilization.Vaucheria sessilisis a rich source of micro- and macronutrients and can be used as a soil amendment. In the paper, the elemental composition of enriched, via bioaccumulation process, macroalga was investigated. For this purpose, two independent techniques were used: scanning electron microscopy with an energy dispersive X-ray analytical system (SEMEDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The biomass was exposed to two microelemental solutions, with Cu(II) and Zn(II) ions. After two weeks of the experiment, macroalga accumulated 98.5 mg of Zn(II) ions in 1 g of dry biomass and 68.9 mg g−1of Cu(II) ions. Micrographs performed by SEM proved that bioaccumulation occurred. Metal ions were bound on the surface and in the interior of cells. Mappings of all cations showed that in the case of the surface of biomass (biosorption), the elements constituted aggregations and in the case of the cross section (bioaccumulation) they were evenly distributed. The algal biomass with permanently bound microelements can find an application in many branches of the industry (feed, natural fertilizers, etc.).


2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola

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.


1997 ◽  
Vol 497 ◽  
Author(s):  
M. H. Jordão ◽  
J. M. Assaf ◽  
P. A. P. Nascente

ABSTRACTCatalysts containing tungsten and nickel oxides are important in hydrodesulfurization (HDS), hydrogénation (HY), and steam reforming of hydrocarbons. A series of W/Ni/Al2O3 catalysts was prepared by two different methods: (1) coprecipitation of nickel and aluminium hydroxicarbonate from their nitrates, followed by calcination and impregnation of tungsten; (2) precipitation of boehmite from aluminium nitrate, followed by impregnations of nickel, firstly, and tungsten. The nickel content was kept constant, while the amount of tungsten varied from 2.5 to 15.5 wt-%. The resulting oxides were characterized by inductively coupled plasma spectroscopy (ICP), atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). ICP and AAS were used to determine the W, Ni, and Al concentrations. XRD detected two phases: NiO and NiAl2O4 (no phase containing metallic tungsten was detected). Increasing the amount of W, the quantity of NiAl2O4 rose, the quantity of NiO decreased, and the particle size of NiO enlarged. The TPR profiles presented three peaks: one at about 1000 °C, associated to a very stable phase; for the samples prepared by coprecipitation, the other two peaks corresponded to “free NiO” and a nonstoichiometric aluminate. For the samples prepared by impregnation, those peaks corresponded to NiO and NiAl2O4. XPS identified Al2O3, NiAl2O4, and Al2(WO4)3 for both preparation methods. Increasing the amount of tungsten in the impregnated samples, NiWO4 was also observed.


Sign in / Sign up

Export Citation Format

Share Document