Adel S. Faidah

Adsorption sites of hydrogen atom on pure and Mg-doped multi-walled carbon nanotubes

Hydrogen adsorption sites on pure multiwalled carbon nanotube (MWCNT) and Mg-doped MWCNTs material system have been investigated using molecular dynamics (MD) simulations as well as quantum chemical calculations. Through combining MWCNTs with Mg, the hydrogen adsorption sites energy on this Mg-MWCNTs system is found to be larger than that of the pure MWCNTs. Additionally, it was found that, through Mg-doping, new adsorption sites for hydrogen molecules are created in comparison with undoped nanotubes. It is also found that H atom is preferably adsorbed at every place near magnesium atom.

Synthesis and characterisation of tin dioxide nanoparticles and effect of annealing temperature

Nanopowder of SnO2 was successfully synthesised by the chemical co-precipitation technique. The product sample was characterised by transmission electron microscope (TEM), X-ray diffraction (XRD) and UV-visible absorption spectrum. Analysis shows that the nanomaterial is found to be phase-pure and nanocrystalline, with a mean particle size around 50 nm. The maximum absorption is observed at around 320 nm. Effect of different annealing temperature on the particle size and shape are also studied. There is no change in the shape and size of these nanoparticles, while annealing them at temperatures ranging from 300°C-600°C. This suggests that the prepared nanoparticles might be useful as gas sensors at hot environments.

Synthesis and characterisation of amorphous SeTe nanorods prepared by ball milling

The amorphous Se97Te3 nanorods were prepared by mechanical milling. The amorphous Se97Te3 materials were used as a starting material. The milled materials were characterisation by XRD, TEM and optical measurement by JASCO, UV/VIS/NIR spectrophotometer in a wavelength region 300 nm-1000 nm. The experimental result shows that an amorphous stage is also achieved during the milling process. TEM analysis showed that after 50 hours of milling time, multi-walled amorphous nanorods were formed with a diameter of about 90 nm and after 60 hours of milling time amorphous nanowires of about 80 nm diameter was formed. The optical absorption measurement indicates that the absorption mechanism is due to indirect transition. It has been observed that the absorption coefficient increases lineally with the increase in photon energy and the optical band gap increases with the increase of milling time.