scholarly journals Mesoporous Ni–Fe Alloys

2008 ◽  
Vol 26 (8) ◽  
pp. 581-588
Author(s):  
Yu Okuno ◽  
Yoshiyuki Hattori ◽  
Tomonori Ohba ◽  
Katsumi Kaneko ◽  
Hirofumi Kanoh
Keyword(s):  
Crystal Structure ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Adsorption ◽  
Inert Atmosphere ◽  
Poly Vinyl Alcohol ◽  
Polymer Precursor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fe Alloys ◽  
Original Crystal

A nano-structured alloy of Ni and Fe was prepared using poly(vinyl alcohol) (PVA) as a polymer precursor, followed by the reduction of Ni2+ and Fe3+ ions to the corresponding metals by heat treatment of the PVA film containing the metal ions under an inert atmosphere. The alloy obtained was characterized by nitrogen adsorption studies, X-ray diffraction and electron microscopy measurements, and by X-ray photoelectron spectroscopy. The nano-structured alloy had the same crystal structure as that of metallic Ni although metallic Fe formed a different structure. The introduction of Fe atoms caused disorder and less crystallinity in the crystal structure of the alloy, whereas Ni atoms tended to maintain the original crystal structure. Nitrogen adsorption measurements at 77 K showed that the nano-structured Ni–Fe alloy contained mesopores of 4–10 nm in diameter.

scholarly journals Study on the Electrical, Structural, Chemical and Optical Properties of PVD Ta(N) Films Deposited with Different N2 Flow Rates

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 937
Author(s):  
Yingying Hu ◽  
Md Rasadujjaman ◽  
Yanrong Wang ◽  
Jing Zhang ◽  
Jiang Yan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
Crystal Size ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Flow Rates ◽  
X Ray ◽  
N2 Flow Rate

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, depending on the crystal size and crystal phase structure.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

A Stand-Alone Mesoporous Crystal Structure Model from in situ X-ray Diffraction: Nitrogen Adsorption on 3 D Cagelike Mesoporous Silica SBA-16

2012 ◽  
Vol 18 (33) ◽  
pp. 10300-10311 ◽  
Author(s):  
Keiichi Miyasaka ◽  
Hiroko Hano ◽  
Yoshiki Kubota ◽  
Yangzheng Lin ◽  
Ryong Ryoo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mesoporous Silica ◽  
Nitrogen Adsorption ◽  
Structure Model ◽  
X Ray Diffraction ◽  
X Ray

SYNTHESIS, CHARACTERIZATION AND THE APPLICABILITY OF β-CYCLODEXTRINS FUNCTIONALIZED MESOPOROUS SBA-15 MOLECULAR SIEVES

NANO ◽  
2013 ◽  
Vol 08 (05) ◽  
pp. 1350050
Author(s):  
MIN GUAN ◽  
HAI-PENG BI ◽  
ZUYUAN WANG ◽  
SHAOHUA BU ◽  
LING HUANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Molecular Sieves ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Capacities ◽  
Transmission Electron ◽  
Potential Applications ◽  
Adsorption Desorption

Mesoporous silicas SBA-15 are modified with β-Cyclodextrins (β-CD) by simple grafting method. β-CD functionalized SBA-15 was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), nitrogen adsorption–desorption measurements, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Furthermore, the applicability of it is investigated through studying the adsorption properties of clenbuterol. It showed better adsorption capacities of clenbuterol than pure SBA-15. β-CD functionalized SBA-15 material has the potential applications in the treatment of clenbuterol contamination in food and environment science.

scholarly journals Preparation of GO/MIL-101(Fe,Cu) composite and its adsorption mechanisms for phosphate in aqueous solution

2021 ◽  
Author(s):  
You Wu ◽  
Zuannian Liu ◽  
Bakhtari Mohammad Fahim ◽  
Junnan Luo
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Adsorption Mechanism ◽  
Nitrogen Adsorption ◽  
Adsorption Properties ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Mechanisms ◽  
Adsorption Desorption

Abstract In this study, MIL-101(Fe), MIL-101(Fe,Cu), and Graphene Oxide (GO) /MIL-101(Fe,Cu) were synthesized to compose a novel sorbent. The adsorption properties of these three MOFs-based composites were compared toward the removal of phosphate. Furthermore, the influencing factors including reaction time, pH, temperature and initial concentration on the adsorption capacity of phosphate on these materials as well as the reusability of the material were discussed. The structure of fabricated materials and the removal mechanism of phosphate on the composite material were analyzed by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analysis and zeta potential. The results show that the maximum adsorption capacity of phosphate by the composite GO/MIL-101(Fe,Cu)-2% was 204.60 mg·g− 1, which is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe). likewise the specific surface area of GO/MIL-101(Fe,Cu)-2% is 778.11 m2/g is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe),which are 747.75 and 510.66m2/g respectively. The adsorption mechanism of phosphate is electrostatic attraction, form coordination bonds and hydrogen bonds. The fabricated material is a promising adsorbent for the removal of phosphate with good reusability.

scholarly journals Improvement of Sensing Performance of Impedancemetric C2H2 Sensor Using SmFeO3 Thin-Films Prepared by a Polymer Precursor Method

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 773 ◽  
Author(s):  
Tomohisa Tasaki ◽  
Satoko Takase ◽  
Youichi Shimizu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Precursor Solution ◽  
Particle Growth ◽  
Polymer Precursor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensor Material ◽  
Perovskite Type

A sensitive an impedancemetric acetylene (C2H2) gas sensor device could be fabricated by using perovskite-type SmFeO3 thin-film as a sensor material. The uniform SmFeO3 thin-films were prepared by spin-coating and focusing on the effects of polymer precursor solutions. The prepared precursors and thin-films were characterized by means of thermal analysis,　Fourier-transform infrared spectroscopy, ultraviolet–visible spectroscopy, X-ray diffraction analysis, scanning electron microscopy and X-ray photoelectron spectroscopy . It was found that particle growth and increase in homogeneity of the prepared thin-film could be accelerated by the addition of acetyl acetone (AcAc) as a coordination agent in the polymer precursor solution. Moreover, the highly crystallized thin-film-based sensor showed good response properties and stabilities to a low C2H2 concentration between 0.5 and 2.0 ppm.

scholarly journals Complete chemical and structural characterization of selenium-incorporated hydroxyapatite

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Baris Alkan ◽  
Caner Durucan
Keyword(s):  
Crystal Structure ◽  
Photoelectron Spectroscopy ◽  
Chemical Properties ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dual Functional ◽  
Tissue Replacement ◽  
Anticancer Effects ◽  
Post Synthesis

AbstractHydroxyapatite (HAp) has long been used as synthetic bone tissue replacement material. Recent advances in this area have led to development of dual-functional bioceramics exhibiting high biocompability/osteoconductivity together with the therapeutic effect. Selenium, in that respect, is an effective therapeutic agent with promising antioxidant activity and anticancer effects. In this study, selenium-incorporated hydroxyapatite (HAp:Se) particles have been synthesized by modified aqueous precipitation method using calcium (Ca(NO3)2·4H2O) and phosphate ((NH4)2HPO4) salts and sodium selenite (Na2SeO3). The effects of selenium incorporation and post-synthesis calcination treatment (900–1100 °C) on physical, chemical properties and crystal structure of resultant HAp powders have been investigated. Complete chemical identification was performed with spectroscopical analyses including Fourier transform infrared and x-ray photoelectron spectroscopy to elucidate the mechanism and chemical nature of selenium incorporation in HAp. Meanwhile, detailed x-ray diffraction studies by Rietveld refinement have conducted to explain changes in the HAp crystal structure upon selenium incorporation.

scholarly journals Study on Hydrogenation Performance of Oil-Soluble Molybdenum Catalyst in Coal-Oil Co-Processing

2022 ◽  
Author(s):  
Guangyao Wang ◽  
Xiqian Wang ◽  
Yuan Zhao
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Heavy Fraction ◽  
X Ray Diffraction ◽  
Molybdenum Catalyst ◽  
X Ray ◽  
Transmission Electron ◽  
Novel Method ◽  
Scanning Electron

Abstract An oil-soluble molybdenum catalyst was synthesized by a simple and novel method and studied for hydrogenation in coal-oil co-processing. The catalyst was characterized by infrared spectrum (IR), thermogravimetry (TG), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The morphology and crystal structure of catalyst was characterized with scanning electron microscope (SEM) and high resolution transmission electron microscopy (HRTEM). The catalyst can be considered as a precursor that can be converted into active MoS2 components through thermal decomposition and sulfidation. The hydrogenation experiment was carried out by the model reactants of tetradecane and 2-methylnaphthalene with a change of reaction (405℃-445℃) temperature and concentrations of molybdenum catalyst (Mo conc. 0.6-10 mg/g), and results showed that the delightly hydrogenation function of catalyst is to improve the saturation of aromatic ring. The most abundant stacking numbers of decomposed catalyst were 2 and 3, accounting for 53% of all catalyst microcrystalline units. The rapid hydrogenation stage and the significant decrease of feed heavy fraction in co-processing experiment provided the evidence that the hydrogenation performance of the synthesized catalyst is remarkable in coal-oil co-processing.

scholarly journals Physicochemical Characteristics of the Birnessite and Todorokite Synthesized Using Various Methods

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 884
Author(s):  
Soyoung Min ◽  
Yeongkyoo Kim
Keyword(s):  
Crystal Structure ◽  
Photoelectron Spectroscopy ◽  
Physicochemical Characteristics ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
Manganese Nodules ◽  
X Ray ◽  
Mineral Phases ◽  
Physicochemical Features ◽  
Scanning Electron

The synthesis methods used to produce todorokite (10 Å manganate, OMS-1) and birnessite (7 Å manganate), which are abundant in marine manganese nodules, have been studied to confirm whether pure mineral phases can be obtained and to compare their physicochemical characteristics. The physicochemical characteristics of todorokite and its precursor Na–birnessite can vary widely based on the precursors used during their synthesis. Birnessite can be synthesized via three mechanisms, i.e., the oxidation of Mn2+, a redox reaction between Mn2+ and MnO4−, or the reduction of MnO4−. Herein, four precursors are used to synthesize birnessite using different methods before being transformed into todorokite. The characteristics of the birnessite and todorokite synthesized using different methods are investigated via X-ray diffraction (XRD), chemical analysis, Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (SEM). Based on the method used, birnessite and todorokite exhibit distinct physicochemical features, including crystallinity, crystal structure, specific surface area, oxidation state of manganese, thermal stability, and morphology. Thus, the characteristics of birnessite and todorokite are closely correlated, indicating the importance of designing suitable methods to synthesize them for specific applications.

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