Search results for "Nitride"

Selective photocatalytic oxidation of 5-hydroxymethyl-2-furfural in aqueous suspension of polymeric carbon nitride and its adduct with H2O2 in a sola…

2018

Abstract This work reports a study on the reactivity of polymeric carbon nitride (PCN) and PCN-H2O2 adduct samples for sunlight photocatalytic selective oxidation reactions. The characterization of these materials was reported in a previous paper where the reactivity towards the partial oxidation of 5-hydroxymethylfurfural (HMF) was studied by using two different laboratory scale photoreactors; one irradiated by UV lamps and the other one by natural sunlight. In the present study it has been confirmed the effectiveness of these C3N4 based materials for the selective partial oxidation of HMF to FDC (2,5-furandicarboxaldehyde) in aqueous medium in a pilot plant photoreactor irradiated by natu…

Aluminium nitrate ceramics: a potential UV dosemeter material.

2002

The ceramic material AlN-Y 2 O 3 is proposed as a potential ultraviolet radiation (UVR) dosemeter using optically stimulated luminescence (OSL) and thermally stimulated luminescence (TL). Experimental studies have shown that AlN ceramics exhibit attractive characteristics suitable for practical UV dosimetry applications. The features are: (1) the spectral sensitivity covers the 200-350 nm range, in the UV-B region it is similar to that of human skin; (2) the angular dependence of the incident radiation follows the cosine law; (3) high yields of both UVR-induced OSL and TL signals compared to those of Al 2 O 3 :C; and (4) a large dynamic range TL signal (5 orders of magnitude). Although ther…

Photocatalytic degradation of 4-Nitrophenol by g-C3N4-MCy: Mechanism study and kinetic modeling

2021

Abstract A graphitic carbon nitride (g-C3N4-MCy) photocatalyst was prepared by thermal condensation of melamine and cyanuric acid with equal proportions. The photocatalyst was characterized by Fourier transform infrared spectroscopy (FTIR), Specific surface area (SSA), X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Transmission electron microscope (TEM), and DRS–UV–Vis spectroscopic methods. We studied the photo-degradation kinetics of 4-nitrophenol using a g-C3N4-MCy. Four parameters were applied including initial concentration of 4-nitrophenol, amount of catalyst, dissolved oxygen content, and photon flux. The reaction rate constant was shown to be correlate…

Preparation and X-Ray Investigation of Higher Uranium Nitrides

1966

First‐principles modelling of defects in advanced nuclear fuels

2007

In this paper we present and discuss the results of first first-principle modelling of point defects in nitride nuclear fuels. Calculations have been performed using the VASP computer code combined with supercells containing up to 250 atoms. The effective atomic charges, the electronic density redistribution, atomic displacements around U and N vacancies and their formation energies are discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

First-principles calculations on double-walled inorganic nanotubes with hexagonal chiralities

2011

The two sets of commensurate double-walled boron nitride and titania hexagonally-structured nanotubes (DW BN and TiO2 NTs) possessing either armchair- or zigzag-type chiralities have been considered, i.e., (n1,n1)@(n2,n2) or (n1,0)@(n2,0), respectively. For symmetry analysis of these nanotubes, the line symmetry groups for one-periodic (1D) nanostructures with rotohelical symmetry have been applied. To analyze the structural and electronic properties of hexagonal DW NTs, a series of large-scale ab initio DFT-LCAO calculations have been performed using the hybrid Hartree-Fock/Kohn-Sham exchange-correlation functional PBE0 (as implemented in CRYSTAL-09 code). To establish the optimal inter-sh…

Tight-binding study of the optical properties of GaN/AlN polar and nonpolar quantum wells

2009

The electronic structure of wurtzite semiconductor superlattices (SLs) and quantum wells (QWs) is calculated by using the empirical tight-binding method. The basis used consists of four orbitals per atom (sp3 model), and the calculations include the spin-orbit coupling as well as the strain and electric polarization effects. We focus our study on GaN/AlN QWs wells grown both in polar (C) and nonpolar (A) directions. The band structure, wave functions and optical absorption spectrum are obtained and compared for both cases.

A Novel High‐Pressure Tin Oxynitride Sn 2 N 2 O

2020

Chemistry - a European journal in Press(in Press), chem.201904529 (2019). doi:10.1002/chem.201904529

Diffusion stabilizes cavity solitons in bidirectional lasers

2009

We study the influence of field diffusion on the spatial localized structures (cavity solitons) recently predicted in bidirectional lasers. We find twofold positive role of the diffusion: 1) it increases the stability range of the individual (isolated) solitons; 2) it reduces the long-range interaction between the cavity solitons. Latter allows the independent manipulation (writing and erasing) of individual cavity solitons.

Pd nanoparticles immobilized on the poly-dopamine decorated halloysite nanotubes hybridized with N-doped porous carbon monolayer: A versatile catalys…

2020

A hybrid catalyst, Pd@Hal-pDA-NPC, with the utility for promoting both C–C coupling reactions (Sonogashira, Heck and Suzuki reactions) and hydrogenation of nitrocompounds is prepared through two main steps. First, Pd(0) nanoparticles was immobilized on the poly-dopamine decorated halloysite nanotubes (Hal-pDA) and then Pd@Hal-pDA was hybridized with the layers of a novel multi-N-doped porous carbon monolayer derived from 4,4′,4″-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))tribenzonitrile. The results established that the catalyst could catalyze all the reactions efficiently under mild reaction condition. Moreover Pd@Hal-pDA-NPC exhibited high recyclability (up to ten reac…