Band bending at the heterointerface of GaAs/InAs core/shell nanowires monitored by synchrotron X-ray photoelectron spectroscopy

ZnO nanowires of approximately 3 µm length and 200 nm diameter are prepared and implanted vertically on substrate glass which is coated with thin layer of ITO which is too covered with bulk ZnO thin layer via electrodeposition process by cyclic voltammetry-chronoamperometry and with a chemical process that is described later; we have synthesized a ZnS nanolayer. ZnO/ZnS core/shell nanowires are formed by ZnO nanowires core surrounded by a very thin layer of porous ZnS shell principally constituted with a crystal which is about 15–20 nm in diameter. In the method, ZnS nanoparticles were prepared by reaction of ZnO nanowires with Na2S in aqueous solution at low temperature and also we have discussed the growth mechanism of ZnO/ZnS nanowires. The morphology, structure, and composition of the obtained nanostructures were obtained by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). For the structure, SEM and XRD measurements indicated that the as-grown ZnO nanowires microscale was of hexagonal wurtzite phase with a high crystalline quality, and TEM shows that the ZnS is uniformly distributed on the surface of the ZnO nanowires.

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Chemical in‐depth analysis of (Ca/Sr)F 2 core–shell like nanoparticles by X‐ray photoelectron spectroscopy with tunable excitation energy

Surface and Interface Analysis ◽

10.1002/sia.6937 ◽

2021 ◽

Vol 53 (5) ◽

pp. 494-508

Author(s):

Anja Müller ◽

Thoralf Krahl ◽

Jörg Radnik ◽

Andreas Wagner ◽

Carsten Kreyenschulte ◽

...

Keyword(s):

Excitation Energy ◽

Photoelectron Spectroscopy ◽

Core Shell ◽

X Ray ◽

Depth Analysis

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Core-shell and gradient morphology polymer particles analyzed by X-ray photoelectron spectroscopy: Effect of monomer feed order

Journal of Polymer Science Part A Polymer Chemistry ◽

10.1002/pola.28644 ◽

2017 ◽

Vol 55 (15) ◽

pp. 2513-2526 ◽

Cited By ~ 4

Author(s):

Florent Jasinski ◽

Victoria L. Teo ◽

Rhiannon P. Kuchel ◽

Monique Mballa Mballa ◽

Stuart C. Thickett ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Core Shell ◽

Polymer Particles ◽

X Ray ◽

Monomer Feed

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Lead-Free BNT–BT0.08/CoFe2O4 Core–Shell Nanostructures with Potential Multifunctional Applications

Nanomaterials ◽

10.3390/nano10040672 ◽

2020 ◽

Vol 10 (4) ◽

pp. 672

Author(s):

Marin Cernea ◽

Roxana Radu ◽

Harvey Amorín ◽

Simona Gabriela Greculeasa ◽

Bogdan Stefan Vasile ◽

...

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Sol Gel ◽

Molar Ratio ◽

Transmission Electron Microscopy Data ◽

Core Shell ◽

Shell Nanoparticles ◽

Two Phase ◽

X Ray ◽

Shell Nanostructures

Herein we report on novel multiferroic core–shell nanostructures of cobalt ferrite (CoFe2O4)–bismuth, sodium titanate doped with barium titanate (BNT–BT0.08), prepared by a two–step wet chemical procedure, using the sol–gel technique. The fraction of CoFe2O4 was varied from 1:0.5 to 1:1.5 = BNT–BT0.08/CoFe2O4 (molar ratio). X–ray diffraction confirmed the presence of both the spinel CoFe2O4 and the perovskite Bi0.5Na0.5TiO3 phases. Scanning electron microscopy analysis indicated that the diameter of the core–shell nanoparticles was between 15 and 40 nm. Transmission electron microscopy data showed two–phase composite nanostructures consisting of a BNT–BT0.08 core surrounded by a CoFe2O4 shell with an average thickness of 4–7 nm. Cole-Cole plots reveal the presence of grains and grain boundary effects in the BNT–BT0.08/CoFe2O4 composite. Moreover, the values of the dc conductivity were found to increase with the amount of CoFe2O4 semiconductive phase. Both X-ray photoelectron spectroscopy (XPS) and Mössbauer measurements have shown no change in the valence of the Fe3+, Co2+, Bi3+ and Ti4+ cations. This study provides a detailed insight into the magnetoelectric coupling of the multiferroic BNT–BT0.08/CoFe2O4 core–shell composite potentially suitable for magnetoelectric applications.

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Growth and Optical Properties of GaP, GaP@GaN and GaN@GaP Core-shell Nanowires

MRS Proceedings ◽

10.1557/proc-776-q2.6 ◽

2003 ◽

Vol 776 ◽

Author(s):

Hung-Min Lin ◽

Jian Yang ◽

Yong-Lin Chen ◽

Yau-Chung Liu ◽

Kai-Min Yin ◽

...

Keyword(s):

Phonon Mode ◽

Piezoelectric Effect ◽

Lattice Mismatch ◽

Core Shell ◽

Photoluminescence Intensity ◽

X Ray ◽

Transmission Electron ◽

Vapor Deposition Technique ◽

Surface Phonon Mode ◽

Shell Nanowires

AbstractHigh-quality GaP, GaP@GaN and GaN@GaP nanowires were grown by a convenient vapor deposition technique. The wire-like and two-layers structures of GaP@GaN and GaN@GaP core-shell nanowires were clearly resolved using X-ray powder diffraction and high-resolution transmission electron microscopy (HRTEM) and their growth directions were identified. Photoluminescence intensity of GaP@GaN nanowires increased as temperature increased. The result was interpreted by the piezoelectric effect induced from lattice mismatch between two semiconductor layers. An unexpected peak at 386 cm-1 was found in the Raman spectra of GaN@GaP and assigned to a surface phonon mode due to the interface. Detailed synthetic conditions and possible growth mechanisms of those nanowires were proposed.

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Fabrication and Characterization of Porous Core–Shell Graphene/SiO2 Nanocomposites for the Removal of Cationic Neutral Red Dye

Applied Sciences ◽

10.3390/app10238529 ◽

2020 ◽

Vol 10 (23) ◽

pp. 8529

Author(s):

Junyi Wang ◽

Tianlu Chen ◽

Biao Xu ◽

Yueqiu Chen

Keyword(s):

Electron Microscopy ◽

Water Vapor ◽

Adsorption Capacity ◽

Photoelectron Spectroscopy ◽

Neutral Red ◽

Water Vapor Adsorption ◽

Core Shell ◽

X Ray ◽

Adsorption Sites ◽

Sio2 Nanocomposites

Porous rGO/SiO2 nanocomposites with a “core-shell” structure were prepared as an efficient adsorbent for the liquid-phase adsorption of cationic neutral red (NR) dye. The samples were characterized with powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TG), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and N2 and water vapor adsorption/desorption methods. The NR removal ability and kinetics of the adsorption process of SiO2 and the rGO/SiO2 nanocomposites were investigated at 298 K. The rGO/SiO2 nanocomposite SG 0.30 showed a superior adsorption of NR dye. In regard to NR at pH 5, we measured a superior adsorption capacity of 66.635 mg/g at an initial NR concentration of 50 mg/L. The experimental adsorption capacity of SG 0.30 was 3.791 times higher than that of SiO2. Then, we compared the results with similar materials used for NR removal. Moreover, the water adsorption sites provided by the nitrogen- and oxygen-containing groups might be one of the reasons for the increased adsorption of water vapor. The broad range of properties of the rGO/SiO2 nanocomposite, including its simple synthesis, ability to be mass prepared, and strong adsorption properties, makes it a truly novel adsorbent that can be industrially produced, and shows potential application in the treatment of wastewater-containing dyes.

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Fe based core–shell model catalysts for the reaction of CO2 with H2

Reaction Kinetics Mechanisms and Catalysis ◽

10.1007/s11144-020-01859-9 ◽

2020 ◽

Vol 131 (1) ◽

pp. 119-128 ◽

Cited By ~ 2

Author(s):

Johann Kirchner ◽

Christian Zambrzycki ◽

Zeynep Baysal ◽

Robert Güttel ◽

Sven Kureti

Keyword(s):

Shell Model ◽

Photoelectron Spectroscopy ◽

Major Product ◽

Model Catalysts ◽

Core Shell ◽

Core Size ◽

X Ray ◽

Transmission Electron ◽

Spent Catalysts ◽

Temperature Programmed

Abstract Fe@SiO2 core–shell model catalysts were investigated for the conversion of CO2 and H2 into CH4, CO and H2O. For evaluation of the effect of core size on the catalytic activity, samples with Fe particle sizes of 4, 6 and 8 nm were prepared. Fresh and spent catalysts were thoroughly characterized by X-ray diffraction, 57Fe Mössbauer spectroscopy, transmission electron microscopy, temperature programmed hydrogenation and X-ray photoelectron spectroscopy. As a result, the yield of the major product CO as well as CH4 was increased with Fe core size. Additionally, growing Fe cores led to stronger carburization and higher amount of reactive carbide entities, which drive the CH4 formation. Finally, formation of inactive bulk carbon deposition is strongly suppressed for the core–shell catalysts in comparison to bulk iron oxide catalysts used for CO2 hydrogenation.

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Combining the Photocatalysis and Absorption Properties of Core-Shell Cu-BTC@TiO2 Microspheres: Highly Efficient Desulfurization of Thiophenic Compounds from Fuel

Materials ◽

10.3390/ma11112209 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2209 ◽

Cited By ~ 11

Author(s):

Jing Liu ◽

Xiao-Min Li ◽

Jing He ◽

Lu-Ying Wang ◽

Jian-Du Lei

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Photocatalytic Oxidation ◽

Uv Light ◽

Sulfur Removal ◽

Oxidation Products ◽

Core Shell ◽

Adsorptive Desulfurization ◽

X Ray ◽

Tio2 Microspheres

A core-shell Cu-benzene-1,3,5-tricarboxylic acid (Cu-BTC)@TiO2 was successfully synthesized for photocatalysis-assisted adsorptive desulfurization to improve adsorptive desulfurization (ADS) performance. Under ultraviolet (UV) light irradiation, the TiO2 shell on the surface of Cu-BTC achieved photocatalytic oxidation of thiophenic S-compounds, and the Cu-BTC core adsorbed the oxidation products (sulfoxides and sulfones). The photocatalyst and adsorbent were combined using a distinct core-shell structure. The morphology and structure of the fabricated Cu-BTC@TiO2 microspheres were verified by scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive x-ray spectroscopy, X-ray powder diffraction, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy analyses. A potential formation mechanism of Cu-BTC@TiO2 is proposed based on complementary experiments. The sulfur removal efficiency of the microspheres was evaluated by selective adsorption of benzothiophene (BT) and dibenzothiophene (DBT) from a model fuel with a sulfur concentration of 1000 ppmw. Within a reaction time of 20 min, the BT and DBT conversion reached 86% and 95%, respectively, and achieved ADS capacities of 63.76 and 59.39 mg/g, respectively. The BT conversion and DBT conversion obtained using Cu-BTC@TiO2 was 6.5 and 4.6 times higher, respectively, than that obtained using Cu-BTC. A desulfurization mechanism was proposed, the interaction between thiophenic sulfur compounds and Cu-BTC@TiO2 microspheres was discussed, and the kinetic behavior was analyzed.

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