Search results for " split"

Nanostructured electrodes for hydrogen production in alkaline electrolyzer

2018

Abstract Ever-widespread employment of renewable energy sources, such as wind and sun, request the simultaneous use of effective energy storage systems owing to the intermittent and unpredictable energy generation by these sources. The most reliable storage systems currently under investigation are batteries and electrochemical cells for hydrogen production from water splitting. Both systems store chemical energy which can be converted on demand. The low power density is the weakness of the batteries while the high production cost limits currently the wide use of hydrogen from electrochemical water splitting. In this work, attention was focused on the use of nanostructured Ni as a cathode f…

Novel TiO2-WO3 self-ordered nanotubes used as photoanodes: Influence of Na2WO4 and H2O2 concentration during electrodeposition

2021

[EN] Hybrid TiO2-WO3 nanostructures has been synthesized by electrochemical anodization under controlled hydrodynamic conditions followed by electrodeposition in the presence of different contents of Na2WO4 (5, 15 and 25 mM) and H2O2 (20, 30 and 40 mM). The influence of the electrolyte used for electrodeposition on the morphology, crystalline structure and photoelectrochemical response for water splitting has been evaluated through Field Emission Electronic Microscopy, High-Resolution Transmission Electron Microscopy, Confocal Raman Spectroscopy, Grazing Incidence X Ray Diffraction, X-Ray Photoelectron Spectroscopy, Atomic Force microscopy and photocurrent versus potential measurements. Add…

Photocatalytic H2 production over inverse opal TiO2 catalysts

2019

Abstract The influence of BiVO4 and CuO on the chemico-physical properties of TiO2-based systems is reported. The performances of these systems were investigated in the photocatalytic H2 production both under UV and solar light irradiation. The characterization data pointed out that the obtained TiO2 samples have highly porous inverse opal structures with interconnected macropores. Inverse opal TiO2 exhibited higher activity in the H2 production than the commercial TiO2 due to the peculiar porosity that allows photons to enter inside the photocatalyst. A further improvement in terms of photoactivity was verified by addition of increasing amounts of BiVO4. On the contrary a small CuO content…

Influence of Co content on structural and magnetic properties of CoxFe84−xNb7B9 alloys

2003

Nanocrystallization of CoxFe84� xNb7B9 (x ¼ 17; 25, 33) alloys has been studied. Crystallization of specimens starts above 4501C. After annealing of specimens in the range 500–7001C, apart from amorphous component and BCC Fe-Co alloy, a non-magnetic component also appears, which is attributed to (Fe1� xCox)2Nb phase with a relative area of about 14%. Decrease of quadrupole splitting with annealing temperature indicates some possible ordering of the nonmagnetic phase. r 2002 Elsevier Science B.V. All rights reserved.

Optical flip-flop memory and routing operation based on polarization bistability in optical fiber

2014

A polarization bistability and hysteresis cycle phenomenon is demonstrated in optical fibers thanks to a counter-propagating four-wave mixing interaction. Based on this process, we successfully report the proof-of-principle of an optical flip-flop memory and a 10-Gbit/s routing operation.

Cathodoluminescence characterization of ZnO/ZnS nanostructures anodized under hydrodynamic conditions

2018

[EN] ZnO/ZnS nanostructures were successfully synthesized by a simple electrochemical anodization of zinc in a glycerol based electrolyte containing sulfide-ammonium fluoride. The influence of different hydrodynamic conditions and anodization potentials during anodization on the morphological and electronic properties of the obtained ZnO/ZnS nanostructures was studied. The anodized samples were characterized using confocal Raman microscopy, X-Ray Diffraction (XRD), Field Emission Scanning Electronic Microscopy (FE-SEM), cathodoluminescence (CL), and photoelectrochemical water splitting tests under standard AM 1.5 conditions. The results showed that hydrodynamic conditions and higher potenti…

Solution-processed Nickel Oxide electrocatalyst for Electrochemical Water Splitting

2020

Correlating the axial Zero Field Splitting with the slow magnetic relaxation in GdIII SIMs

2021

The field-induced out-of-phase magnetic response of a GdIII complex, selected by its good isolation in the network, has been analyzed and the behaviour of this quasi-isotropic cation has been related to its weak axial zero field splitting ∼0.1 cm-1.

Heat-capacity anomaly due to spin reorientation and thermodynamic functions of ErFeO3 and TmFeO3

2001

Abstract Heat capacities of orthoferrites, ErFeO 3 and TmFeO 3 , have been measured below room temperature by adiabatic calorimetry. A broad but definite anomaly due to the spin reorientation phenomenon was successfully detected in the expected temperature range (ca. 90 K). The results are compared with a vast anomaly reported for YbFeO 3 . The temperature dependence of the electric quadrupole splitting of the Fe nuclear levels was determined by Mossbauer spectroscopy through the spin reorientation. A heat capacity anomaly centered at 3.60 K due to the magnetic ordering of Er 3+ ions was clearly detected. Some Schottky anomalies were resolved and energy splittings involved were roughly esti…

EPR Study of Gd3+local structure in ScF3crystal with negative thermal expansion coefficient

2015

Zero field splitting (ZFS) of Gd3+ impurity in ScF3 is studied by electron paramagnetic resonance at 77 and 295 K. ZFS parameter b4 values obtained from angular dependence simulations show that regardless of negative thermal expansion in ScF3 temperature dependence of |b4| is similar to other cubic fluoroperovskites. Our analysis of ZFS parameters indicates that the local structure of Gd3+ centres expands positively with temperature.