Simultaneous effects of hydrostatic pressure and geometry on metal-insulator transition in a cubical quantum dot

The ionization energies of a hydrogenic donor in a GaAs- Ga1-xAlxAs cubical quantum dot system are obtained for various cross-sectional geometries. We have investigated the metal -insulator transition in such a system by considering the simultaneous effects of pressure and geometry. It is observed that, the ionization energies are increased due the geometry effect. Consecutively, the metal insulator transition couldn’t occur for lower concentration of donor impurities. We present the results for infinite confinement. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2790

Synthesis and Characterization of Polymer (Sulfonated Poly-ether-ether-ketone) Based Nanocomposite (h-boron nitride) Membrane for Hydrogen Storage

The development of light weight and compact hydrogen storage materials is still prerequisite to fuel-cell technology to be fully competitive. The present experimental study reports the hydrogen storage capability of sulfonated poly-ether-ether-ketone (SPEEK)-hexagonal boron nitride (h-BN) (SPEEK-h-BN) nanocomposite membranes. The nanocomposite membranes are prepared by considering various amount of h-BN (0, 1, 3 and 5 wt. %) by phase inversion technique. The degree of sulfonation of the PEEK (SPEEK) is found to be 65% by Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. Hydrogen adsorption studies have been carried out using a Seiverts-like hydrogenation setup. The membranes are characterized by X-ray Diffractometer (XRD), Micro-Raman spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), CHN-elemental analysis and Thermo Gravimetric Analysis (TGA). It is observed that the SPEEK-5% h-BN membrane performs better than pure SPEEK membrane, has maximum storage capacity of 2.98 wt. % at 150 °C and the adsorbed hydrogen has an average binding energy of 0.38 eV. The TGA study shows the dehydrogenation behavior of hydrogenated SPEEK-h-BN nanocomposite membrane and it is found to be in the temperature range of 214–218 °C for SPEEK-5% h-BN membrane

Hydrogen Adsorption Properties of Multiwalled carbon nanotubes -Hexagonal Boron Nitride Nanocomposite

Abstract: Hydrogen is considered as a promising alternative energy carrier that can potentially facilitate the transition from fossil fuels to sources of clean energy because of its prominent advantages such as high energy density and environment friendly, but one of the major problems limiting the use of hydrogen for energy applications is the difficulty of storing it safely. In this work, the hydrogen storage performance of acid treated multi-walled carbon nanotubes (MWCNT)/hexagonal boron nitride (h-BN) (MWCNT/h-BN) nano composite is investigated. The MWCNT/h-BN nanocomposite is prepared by using drop cast method. The hydrogenation of acid treated MWCNTs and MWCNT/h-BN nano composite have been carried out using Seiverts like apparatus. The prepared nanocomposites were characterized by X-ray Diffraction (XRD), micro-Raman spectroscopy, Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), CHN-elemental analysis and Thermo Gravimetric Analysis (TGA). The amount of hydrogen stored in MWCNT/h-BN nanocomposite is found to be 1.6 wt. % at 100 ºC and the average binding energy of stored hydrogen is 0.48 eV