1,721,164 research outputs found
Fe2O3-TiO2 nanocomposites on activated carbon fibers by a plasma-assisted approach
No full textFe2O3-TiO2 nanocomposites on activated carbon fibers (ACFs) have been fabricated by a two-step plasmaassisted route, involving the plasma enhanced-chemical vapor deposition (PE-CVD) of iron oxide followed by radio frequency (RF) titanium sputtering for different process durations. A multi-technique characterization of the developed systems has been performed by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscopy (FE-SEM), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDXS). The adopted approach enabled the successful preparation of high purity composite nanomaterials, with high surface area and characterized by the co-presence of Fe2O3 and TiO2 in tailored amounts. The homogeneous coverage of ACFs by Fe2O3-TiO2, along with the optimal deposit adhesion to the support, candidate the present Fe2O3-TiO2@ACF nanocomposites as attractive systems for photocatalytic applications
Growth and electro-optical properties of Ga-doped ZnO films prepared by aerosol assisted chemical vapour deposition
No full textXPS analysis of F-containing NiO nanoarchitectures fabricated by plasma-assisted chemical vapor deposition
Full text linkThe oxygen evolution reaction (OER), extensively investigated over the last decade for energy-related end-uses, still remains the bottleneck hindering a large-scale exploitation of water splitting to produce green hydrogen as a clean energy vector. Among the possible electrocatalysts, nanomaterials based on nickel(II) oxide are attracting considerable interest. In this context, the present investigation reports the results of the XPS analysis of NiO nanoarchitectures obtained by plasma-assisted chemical vapor deposition (PA-CVD) on conducting glass substrates from a fluorinated Ni(II) precursor. The growth at two different temperatures (100 and 400 °C) yielded, respectively, quasi-1D structures and polycrystalline porous systems, characterized, respectively, by the occurrence of surface C-F moieties and F distributed in the NiO network. The reported spectra include survey scans and high-resolution spectra of Ni 2p, O 1s, F 1s, and C 1s core-levels, recorded using monochromatic Al-Kα radiation. The present data provide a reference for NiO-based materials deposited by chemical or physical vapor deposition methods
Mn3O4 thin films functionalized with Ag, Au, and TiO2 analyzed using x-ray photoelectron spectroscopy
No full textIn the present contribution, bare and composite Mn3O4 (Mn3O4-X, with X = Ag, Au, or TiO2) thin
films were fabricated by a two-step vapor-phase route, consisting in: (1) chemical vapor deposition
of Mn3O4 on Si(100) substrates starting from a fluorinated b-diketonate diamine Mn(II) complex;
(2) introduction of silver, gold, or titania by means of radio frequency (RF)-sputtering. The
obtained results evidenced the formation of phase-pure a-Mn3O4 thin films chemically modified
with fluorine, which after RF-sputtering yielded Mn3O4-X nanocomposite systems with tailored
properties. In this work, data obtained by x-ray photoelectron spectroscopy characterization of the
surface chemical composition are presented and discussed for bare and functionalized Mn3O4 systems.
In addition to wide scan spectra, particular attention is dedicated to the analysis of C 1s, O
1s, Mn 2p, Mn 3s, F 1s and, eventually, Ag 3d, Au 4d5/2, and Ti 2p core levels, as well as silver
Auger signal. In the case of the Mn3O4-Au system, a quantification procedure aimed at circumventing
problems arising from the overlap of Mn 2p/Au 4p1/2 and Mn 3s/Au 4f signals is proposed
Analysis of Co3O4-SnO2 and Co3O4-Fe2O3 nanosystems by x-ray photoelectron spectroscopy
No full textIn this work, x-ray photoelectron spectroscopy was employed to characterize the surface composition and elemental chemical states of supported Co3O4-SnO2 and Co3O4-Fe2O3 nanocomposites. The present materials were prepared on Si(100) substrates by the chemical vapor deposition of cobalt oxide under O2+ H2O atmospheres, followed by the tailored introduction of SnO2 or Fe2O3 by means of radio frequency-sputtering. Material structural and morphological characterization revealed the formation of nanocomposite heterostructures involving a conformal Co3O4 coverage by SnO2 or Fe2O3 overlayers. Survey spectra as well as detailed scans of C 1s, O 1s, Co 2p, Sn 3d, and Fe2p regions are presented and critically discussed. The results provide evidence for the formation of pure and oxygen-deficient nanocomposites, and the occurrence of an electronic interplay between the single oxide constituents
XPS investigation of F-doped MnO2 nanosystems fabricated by plasma assisted-CVD
No full textSupported Mn(IV) oxide nanomaterials were prepared by plasma assisted-chemical vapor deposition
from Ar/O2 plasmas starting from a fluorinated Mn(II) β-diketonate diamine adduct. Under the
adopted conditions, the target compound served as a single-source molecular precursor for the
obtainment of MnO2 nanosystems uniformly doped with fluorine. The overall F content in the target
materials, composed of phase-pure β-MnO2, could be tailored as a function of the deposition temperature
from 100 to 400 °C, a result of particular importance in view of photocatalytic and gas sensing
applications. In the present study, attention is specifically devoted to the investigation of a representative
specimen by means of x-ray photoelectron spectroscopy. Besides the wide scan spectrum, a
detailed analysis of C 1s, O 1s, Mn 2p, Mn 3s, and F 1s photoelectron peaks is presented and discussed.
The analyses reveal the formation of MnO2 free from other manganese oxides, with fluorine
present in different chemical states, i.e., lattice F plus traces of precursor residuals at the system
surface
Metal/oxide interfaces in inorganic nanosystems: what's going on and what's next?
No full textMetal/oxide nanosystems with different spatial organizations have attracted a remarkable
interest for their unique features and multi-functional properties, which can be finely tuned by
controlling the interplay between their structure, morphology and composition. Their
assembly and ultimate utilization depend indeed on the nature of metal/oxide interfaces, the
birthplaces of a multitude of fascinating phenomena. A detailed insight into interfacial
chemical/physical properties by advanced experimental techniques would thus deliver
significant advantages from both a fundamental and an applicative point of view
CuO/ZnO Nanocomposites Investigated byX-ray Photoelectron and X-ray Excited AugerElectron Spectroscopies
No full textSupported CuO/ZnO nanocomposites were prepared by a novel bottom-up approach, consisting of:
i) deposition of columnar ZnO arrays on Si(100) by Plasma Enhanced-Chemical Vapor Deposition
(PE-CVD) using a Zn(II) bis(ketoiminate) precursor; ii) Radio Frequency (RF)-sputtering of Cu in
Ar atmospheres. Finally, ex-situ annealing was performed in air at 400°C to promote a complete
copper oxidation. The CuO/ZnO nanocomposites were characterised by Glancing Incidence X-ray
Diffraction (GIXRD), Transmission Electron Microscopy (TEM), Field Emission-Scanning
Electron Microscopy (FE-SEM) and Energy Dispersive X-ray Spectroscopy (EDXS), providing
important information on their chemical, morphological and structural properties. In this
contribution, a detailed investigation of a representative sample by X-ray Photoelectron (XPS) and
X-ray Excited Auger Electron (XE-AES) Spectroscopies is presented, with particular attention
to the analysis of O 1s, Zn 2p3/2 and Cu 2p core levels, as well as zinc and copper Auger signals
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