Search results for "O2"
showing 10 items of 1115 documents
Paper Functionalized with Nanostructured TiO2/AgBr: Photocatalytic Degradation of 2–Propanol under Solar Light Irradiation and Antibacterial Activity
2020
A facile method to produce paper&ndash
Phosphomolybdic acid and mixed phosphotungstic/phosphomolybdic acid chitosan membranes as polymer electrolyte for H2/O2 fuel cells
2017
Abstract Flat, free-standing phosphomolybdic acid and mixed phosphotungstic/phosphomolybdic acid chitosan membranes were prepared by in-situ ionotropic gelation process at room temperature on porous alumina support firstly impregnated by heteropolyacid. Scanning electron microscopy revealed the formation of compact and homogenous polymeric membranes, whose thickness resulted to be dependent on reticulation time, and almost independent on the employed heteropolyacid nature and concentration. X-ray diffraction and Fourier transform infrared spectroscopy evidenced the formation of crystalline membranes without appreciable concentration of unprotonated NH 2 groups and heteropolyacid ions with p…
First principles calculations on CeO2 doped with Tb3+ ions
2019
This research was funded by the Latvian Council of Science (under the grant project lzp-2018/1-0147). Authors thank W. Chueh, J. Serra, R. Merkle, A. Popov for fruitful discussions.
A photoemission study of molybdenum hexacarbonyl adsorption and decomposition on TiO2(110) surface.
2007
International audience; The adsorption and decomposition of molybdenum hexacarbonyl on (110) TiO2 surfaces were studied using both core levels and valence band photoemission spectroscopies. It was found that after an adsorption at 140 K, when going back to room temperature, only a small part of molybdenum compounds, previously present at low temperature, remained on the TiO2 surface. This indicates that the desorption temperature on such a surface is lower than the decomposition one. The use of photon irradiation to decompose the hexacarbonyl molecule was also studied. It was shown that during such a decomposition molecular fragments were chemisorbed on the surface allowing a higher amount …
Electrospun TiO2 embedded nanofibers for photocatalytic applications
2019
The development of photocatalysts with low cost, high reactivity and easy recovery provides great potentials for environmental remediation. In this study, polyacrylonitrile (PAN) nanofibers containing titanium dioxide ([Formula: see text]) nanoparticles were successfully fabricated using a facile electrospinning technique. The effects of [Formula: see text] content, PAN concentration and thermal treatment on the adsorption and photocatalysis properties of [Formula: see text] nanofibers have been investigated. The results indicate that the embedded [Formula: see text] nanofibers possess the property to effectively decompose rhodamine B (RhB) under simulated sunlight irradiation. The enhance…
Structural and optical properties of novel surfactant-coated Yb-TiO2 nanoparticle
2010
Abstract In this paper a novel hybrid approach to synthesise composite nanoparticles is presented. It is based on the laser ablation of a bulk target (Yb) immersed in a reversed micellar solution which contains nanoparticles of a different host material (TiO2 nanoparticles) previously synthesised by chemical method. This approach thus exploits the advantages of the chemical synthesis through reversed micellar solution (size control, nanoparticle stabilisation), and of the laser ablation (‘‘clean’’ synthesis, no side reactions). Central role is played by the microscopic processes controlling the deposition of the ablated Yb atoms onto the surface of TiO2 nanoparticles which actually behave a…
Magneto-optical Investigations of Nanostructured Materials Based on Single Molecule Magnets Monitor Strong Environmental Effects
2007
The determination of the magnetic properties of molecular magnets in environments similar to those used in spintronic devices is fundamental for the development of applications. Single-molecule magnets (SMMs) are molecular cluster systems that display magnetic hysteresis of dynamical origin at low temperature. As they behave like perfectly monodisperse nanomagnets and show clear macroscopic quantum effects in their magnetic properties, they are extremely appealing candidates for the forthcoming generation of molecular devices: they have been proposed as efficient systems for quantum computation, ultra-high-density magnetic recording media, and molecular spintronic systems. These attractive …
Ceramic/metal nanocomposites by lyophilization: Spark plasma sintering and hardness
2014
The present study is focused on the procedure of spray-drying and lyophilization techniques for the preparation of ceramic/metal nanocomposites. The results of the study at all stages are compared with those corresponding to powders conventionally dried by heating in furnace. Starting from aqueous solutions of metal salts and ceramic powders, the procedure follows with spray-drying, lyophilization, calcination of the resulting powders and subsequent Spark Plasma Sintering (SPS). X-ray diffraction analysis of the powders at different stages of the processing routes was used for phase indexing; further characterization was performed by Transmission Electron Microscopy and Energy Dispersive X-…
Effect of Hydration Procedure of Fumed Silica Precursor on the Formation of Luminescent Carbon Centers in SiO 2 :C Nanocomposites
2019
The effect of hydration procedure of fumed silica precursor on photoluminescent properties of carbonized silica (SiO2:C) nanocomposite after chemo/thermal treatments is studied. Main structural effect is the formation of chemical bonding of phenyl groups to silica surface via multiple CSiO bonding bridges. Synthesized samples demonstrate very broad photoluminescence (PL) bands in near ultraviolet and visible ranges with maximum intensity dependent on temperature of thermal annealing. Two main trends in luminescence properties are: 1) hydration-induced blue shift of PL in comparison with PL of unhydrated series; 2) red shift of PL bands with increasing synthesis temperature regardless hydr…
The role of impurities in the irradiation induced densification of amorphous SiO(2).
2011
In a recent work (Buscarino et al 2009 Phys. Rev. B 80 094202), by studying the properties of the (29)Si hyperfine structure of the E'(γ) point defect, we have proposed a model able to describe quantitatively the densification process taking place upon electron irradiation in amorphous SiO(2) (a-SiO(2)). In particular, we have shown that it proceeds heterogeneously, through the nucleation of confined densified regions statistically dispersed into the whole volume of the material. In the present experimental investigation, by using a similar approach on a wider set of materials, we explore how this process is influenced by impurities, such as OH and Cl, typically involved in relevant concent…