Search results for " split"

Nuclear Quadrupole Moment of 119Sn

2008

Second-order scalar-relativistic Douglas-Kroll-Hess density functional calculations of the electric field gradient, including an analytic correction of the picture change error, were performed for 34 tin compounds of which molecular structures and Sn-119 Mossbauer spectroscopy parameters are experimentally known. The components of the diagonalized electric field gradient tensor, V-xx,V-yy, V-zz, were used to determine the quantity V, which is proportional to the nuclear quadrupole splitting parameter Delta E. The slope of the linear correlation plot of the experimentally determined Delta E parameter versus the corresponding calculated V data allowed us to obtain an absolute value of the nuc…

Aromaticity and planarity of zinc phthalocyanine (ZnPc) characterized by splitting of NICS(1) index

2018

The planarity of zinc phthalocyanine (ZnPc) in the gas phase and water, with solute-solvent interactions modeled by polarized continuum model (PCM), has been characterized with new indexes of aromaticity. The aromaticity of individual ring subunits of ZnPc molecule was studied on the basis of nucleus independent chemical shift index (NICS) above and below the molecular plane. Density functional theory (DFT) with selected Pople-type basis sets was used to study the local aromaticity. The calculated NICS(1) and NICS(-1) indexes of aromaticity for a non-planar ZnPc molecule in the polar environment are significantly different.

Doped 1D Nanostructures of Transition-metal Oxides: First-principles Evaluation of Photocatalytic Suitability

2016

Structure-Directing and High-Efficiency Photocatalytic Hydrogen Production by Ag Clusters

2014

H2 production by water splitting is hindered mainly by the lack of low-cost and efficient photocatalysts. Here we show that sub-nanometric silver clusters can catalyze the anisotropic growth of gold nanostructures by preferential adsorption at certain crystal planes of Au seeds, with the result that the final nanostructure can be tuned via the cluster/seed ratio. Such semiconducting Ag clusters are extremely stable and retain their electronic structure even after adsorption at the tips of Au nanorods, enabling various photocatalytic experiments, such as oxygen evolution from basic solutions. In the absence of electron scavengers, UV irradiation generates photoelectrons, which are stored wit…

Formation of ZnO nanowires by anodization under hydrodynamic conditions for photoelectrochemical water splitting

2020

[EN] The present work studies the influence of hydrodynamic conditions (from 0 to 5000 rpm) during Zn anodization process on the morphology, structure and photoelectrocatalytic behavior of ZnO nanostructures. For this purpose, analysis with Confocal Laser-Raman Spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM) and photoelectrochemical water splitting tests were performed. This investigation reveals that hydrodynamic conditions during anodization promoted the formation of ordered ZnO nanowires along the surface that greatly enhance its stability and increases the photocurrent density response for water splitting in a 159% at the 5000 rpm electrode rotation speed.

Controlled hydrodynamic conditions on the formation of iron oxide nanostructures synthesized by electrochemical anodization: Effect of the electrode …

2017

[EN] Iron oxide nanostructures are of particular interest because they can be used as photocatalysts in water splitting due to their advantageous properties. Electrochemical anodization is one of the best techniques to synthesize nanostructures directly on the metal substrate (direct back contact). In the present study, a novel methodology consisting of the anodization of iron under hydrodynamic conditions is carried out in order to obtain mainly hematite (alpha-Fe2O3) nanostructures to be used as photocatalysts for photoelectrochemical water splitting applications. Different rotation speeds were studied with the aim of evaluating the obtained nanostructures and determining the most attract…

Improvement in photocatalytic activity of stable WO3 nanoplatelet globular clusters arranged in a tree-like fashion: Influence of rotation velocity d…

2016

This study investigates the influence of controlled hydrodynamic conditions during anodization of tungsten (W) on the morphological, electrochemical and photocatalytic properties of a novel WO3 nanostructure: globular clusters of nanoplatelets associated in a tree-like fashion. For this purpose different techniques such as Field-Emission Scanning Electronic Microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS) measurements, Mott-Schottky (M-S) analysis and photoelectrochemical water splitting tests have been carried out. Photoanodes obtained at 375 rpm showed the best photoresponse, much higher than that of conventional WO3 nanoplatelets, which can be ascribed to a noteworthy in…

Time-Dependent Density Functional Theory Calculations of N- and S-Doped TiO2 Nanotube for Water-Splitting Applications

2021

This research was funded by the Latvian Council of Science grant LZP-2018/2-0083. Institute of Solid State Physics, University of Latvia, as the Center of Excellence, has received funding from the European Union?s Horizon 2020 Framework Program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under Grant Agreement No. 739508, project CAMART2.

First principles modeling of 3d-metal doped three-layer fluorite-structured TiO2 (4,4) nanotube to be used for photocatalytic hydrogen production

2017

This study has been supported by the EC ERA.Net RUS Plus project No. 237 WATERSPLIT, Russian Basic Research Foundation No. 16-53-76019, and additionally by the IMIS2 Program (Latvia). The authors are also indebted to R. A. Evarestov and O. Lisovski for stimulating discussions as well as to A. Chesnokov for technical assistance.

Enhancement of photoelectrochemical activity for water splitting by controlling hydrodynamic conditions on titanium anodization

2015

This work studies the electrochemical and photoelectrochemical properties of a new type of TiO2 nanostructure (nanosponge) obtained by means of anodization in a glycerol/water/NH4F electrolyte under controlled hydrodynamic conditions. For this purpose different techniques such as Scanning Electronic Microscopy (SEM), Raman Spectroscopy, Electrochemical Impedance Spectroscopy (EIS) measurements, Mott–Schottky (M−S) analysis and photoelectrochemical water splitting tests under standard AM 1.5 conditions are carried out. The obtained results show that electron–hole separation is facilitated in the TiO2 nanosponge if compared with highly ordered TiO2 nanotube arrays. As a result, nanosponges en…