Search results for "XPS"
showing 10 items of 66 documents
Perfluorocarbons–graphene oxide nanoplatforms as biocompatible oxygen reservoirs
2018
Abstract 3-Pentadecafluoroheptyl,5-perfluorophenyl-1,2,4-oxadiazole (FOX) molecules were attached onto a graphene oxide (GO) via a facile aromatic substitution in alkaline environment. This approach allows achieving high degree of functionalization under mild conditions. The covalent attachment of perfluoromoieties onto GO lamellae was confirmed by spectroscopic analyses. The performance of these nanoplatforms (GOF) as oxygen reservoirs was assessed at different concentrations and temperature. The results revealed that under physiologic conditions GO and FOX synergistically operate for increasing oxygen uptake and release, either from a thermodynamic and a kinetic point of view. Even at low…
Water splitting through model surfaces of metal oxides : ferroelectric polarization towards water adsorption processes
2019
The properties of out-of-plane polarized BaTiO3(001) thin films were investigated from first-principles calculations and photoemission spectroscopy. Firstly, density functional theory calculations (DFT) were used to unravel the nature of the Pt(001)/BaTiO3(001) interface. In particular, the influence of the substrate on the ferroelectric properties of the BaTiO3 overlayer has been studied. Among the results, it can be pointed that platinum tends to increase the ferroelectric domain size of BaTiO3.Then, the adsorption of water on BaTiO3 was described by means of DFT calculations. The impact of the polarization as well as the influence of the nature of the surface termination on water adsorpt…
Influence of post-treatment time of trivalent chromium protection coating on aluminium alloy 2024-T3 on improved corrosion resistance
2019
Abstract Low corrosion protection performances of Trivalent Chromium Process (TCP) coatings with reference to Chromium Conversion Coatings (CCC) deposited on aluminium alloys can be overcome by application of post-treatment processes. This work shows the effect of post-treatment bath (containing hydrogen peroxide and lanthanum salt) on the chemical composition, structure and the corrosion performances of TCP coating deposited on AA 2024-T3 aluminium alloy. Different times of post-treatment bath were applied on the TCP coating and the samples were analyzed by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), X-ray Photoelectron Spectroscopy (XPS) and Glow Discharge-Optical Emission …
Elaboration and characterization of barium silicate thin films.
2008
International audience; Room temperature depositions of barium on a thermal silicon oxide layer were performed in ultra high vacuum (UHV). In-situ X-ray photoelectron spectroscopy (XPS) analyses were carried out as well after exposure to air as after subsequent annealings. These analyses were ex-situ completed by secondary ion mass spectrometry (SIMS) profiles and transmission electron microscopy (TEM) cross-sectional images. The results showed that after air exposure, the barium went carbonated. Annealing at sufficient temperature permitted to decompose the carbonate to benefit of a barium silicate. The silicate layer was formed by interdiffusion of barium with the initial SiO2 layer.
Understanding the Conversion Process of Magnetron-Deposited Thin Films of Amorphous ReO$_x$ to Crystalline ReO$_3$ upon Thermal Annealing
2020
Crystal growth & design 20(9), 6147 - 6156 (2020). doi:10.1021/acs.cgd.0c00848
Effect of NaClO disinfection/cleaning on passive films on AISI 316L
2020
Abstract 316 L stainless steel samples were passivated in NaClO containing solutions in order to simulate disinfection processes. Passive films were grown at the open circuit potential by immersion in NaClO aqueous solutions at different concentrations and temperature in order to understand how exposure to aggressive environments could affect subsequent corrosion resistance of SSs. In the attempt to study the passive film growth mechanism, in-situ Open Circuit Potential measurements were performed in the same growth solutions. Photoelectrochemical and impedance investigation of passive films was carried out in order to link their solid state properties with their corrosion behaviour.
H2-TPR, XPS and TEM Study of the Reduction of Ru and Re promoted Co/γ-Al2O3, Co/TiO2 and Co/SiC Catalysts
2016
<p class="1Body">Effects of Ru and Re promoters on Co-CoO<sub>x </sub>catalysts supported on γ-Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub> and SiC were investigated to improve the understanding of the role of promoters of the active phase of Co-CoO<sub>x</sub>-Ru and Co-CoO<sub>x</sub>-Re. The influence of promoter addition on the composition and activity of the catalysts was characterized by several methods, such as H<sub>2</sub>-TPR, XPS, chemisorption and TEM. Furthermore, the role of support and metal-support interaction was especially studied and different support materials were compared.</p&g…
Template Electrochemical Growth and Properties of Mo Oxide Nanostructures
2014
This work is aimed at studying the growing process of nanostructures electrodeposited from molybdate aqueous solutions at different pH values into pores of polycarbonate membrane templates. The challenging issue was the opportunity to investigate a rather complex deposition process in a confined ambient, where electrochemical conditions are quite different from those usually established for deposition on a flat substrate. Nanostructures were grown from a bath containing Mo7O246– (NH4)6Mo7O24·4H2O) at different concentrations (50–100 g/L), at a constant cathodic current density of 2 mA/cm2 (electrodeposition area ∼8 cm2). Nanostructured deposit was characterized by XRD, EDS, Raman, XPS, and …
Optical modeling of nickel-base alloys oxidized in pressurized water reactor
2012
International audience; The knowledge of the aging process involved in the primary water of pressurized water reactor entails investigating a mixed growth mechanism in the corrosion of nickel-base alloys. A mixed growth induces an anionic inner oxide and a cationic diffusion parallel to a dissolution-precipitation process forms the outer zone. The in situ monitoring of the oxidation kinetics requires the modeling of the oxide layer stratification with the full knowledge of the optical constants related to each component. Here, we report the dielectric constants of the alloys 600 and 690 measured by spectroscopic ellipsometry and fitted to a Drude-Lorentz model. A robust optical stratificati…
Influence of ZnO/graphene nanolaminate periodicity on their structural and mechanical properties
2018
International audience; Structural, electronic and mechanical properties of ZnO/Graphene (ZnO/G) nanolaminates fabricated by low temperature atomic layer deposition (ALD) and chemical vapor deposition (CVD) were investigated. We performed scanning and transmission electron microscopy (SEM/TEM), X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), Raman spectroscopy, X-Ray photoelectron spectroscopy (XPS) and nanoindentation to characterize the ZnO/G nanolaminates. The main structural and mechanical parameters of ZnO/G nanolaminates were calculated. The obtained results were analyzed and interpreted taking into account mechanical interaction and charge effects occurring at the …