Firas K. Mohamad Alosfur

Modified microwave method for the synthesis of visible light-responsive TiO2/MWCNTs nanocatalysts

Recently, TiO2/multi-walled carbon nanotube (MWCNT) hybrid nanocatalysts have been a subject of high interest due to their excellent structures, large surface areas and peculiar optical properties, which enhance their photocatalytic performance. In this work, a modified microwave technique was used to rapidly synthesise a TiO2/MWCNT nanocatalyst with a large surface area. X-ray powder diffraction, field-emission scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller measurements were used to characterise the structure, morphology and the surface area of the sample. The photocatalytic activity of the hybrid nanocatalysts was evaluated through a comparison of the degradation of methylene blue dye under irradiation with ultraviolet and visible light. The results showed that the TiO2/MWCNT hybrid nanocatalysts degraded 34.9% of the methylene blue (MB) under irradiation with ultraviolet light, whereas 96.3% of the MB was degraded under irradiation with visible light.

One-step formation of TiO2 hollow spheres via a facile microwave-assisted process for photocatalytic activity

Mesoporous TiO2 hollow spherical nanostructures with high surface areas were successfully prepared using a microwave method. The prepared hollow spheres had a size range between 200 and 500 nm. The spheres consisted of numerous smaller TiO2 nanoparticles with an average diameter of 8 nm. The particles had an essentially mesoporous structure, with a pore size in the range of 2-50 nm. The results confirmed that the synthesised of anatase TiO2 nanoparticles with specific surface area approximately 172.3 m2 g-1. The effect of ultraviolet and visible light irradiation and catalyst dosage on the TiO2 photocatalytic activity was studied by measuring the degradation rate of methylene blue. The maximum dye degradation performances with low catalyst loading (30 mg) were 99% and 63.4% using the same duration of ultraviolet and visible light irradiation, respectively (120 min).

Voltammetric Characterization of Grafted Polymer Modified with ZnO Nanoparticles on Glassy Carbon Electrode

In this study, a grafted polymer (GP) with ZnO nanoparticles (GP/ZnO NPs) was attached on the surface of glassy carbon electrode (GCE), in order to produce a new modified electrode (GP/ZnO NPs-GCE). The gamma irradiation method was used to grafted polystyrene (polymer) with acrylonitrile (monomer), while slow evaporation process was used to prepare the new modified electrode. The cyclic voltammetry (CV) of K4[Fe(CN)6] was used to study the electrochemical properties GP/ZnO NPs-GCE. The peak separation (ΔEpa-c) was 500 mV between the redox peaks of Fe(II)/Fe(III) in an aqueous solution of 1 M KCl and the current ratio of redox current peaks (Ipa/Ipc) was ≈ 1 for the modified electrode. This indicated that the modified electrode has s good reversibility and conductivity, wherefore; it was applied in the voltammetric filed. It was found that the modified electrode GP/ZnO NPs-GCE have a reasonable solubility and stability at various pH medium. Additionally, the sensitivity of the electrochemical analysis by cyclic voltammetric (CV) method is extensively subjected to the pH medium and the scan rate (SR). A couple of redox current peaks of K4[Fe(CN)6] in KCl solution was observed with a reversible process: Fe3+/Fe2+. Finally a good diffusion coefficient of electroactive species (D) for the new modified electrode was found in this study by chronoamperometry method using Cottrell equation.

Ablation of ZnO in liquid by Nanosecond Laser

Zinc oxide (ZnO) was synthesized by laser ablation in liquid. The preparation steps included immersing ZnO bulk pellet in ethanol and then ablating by Nd-Yag laser. The used laser has a wavelength ranging from 1064 nm to 532 nm with 140 mJ pulse intensity. Structural, morphological and optical properties of the prepared material were investigated by X-ray diffraction, scanning electron microscopy and UV-Vis spectroscopy, respectively. The XRD results revealed the formation of hexagonal ZnO structure with (101) as dominant peak. The SEM studies demonstrated the formation of spherical ZnO nanoparticles which agglomerated to form nanocluster. Typical exciton absorption was observed at 376 nm in the absorption spectrum of UV-Vis spectroscopy at room temperature and the energy gap was equal to (3.48 eV).

Effect of Crushing Speed Rate on Crashworthiness Parameters and Energy Absorption Capability of Composite Materials

Improvement of energy absorber in automotive and aircraft industry is a demanding requirement. Crashworthiness parameters designed to special interesting and could ensure the passengers safety and reduce fuel costs. Thin shells are the main structures of energy absorbing in transportation applications for collisions; it is very important to check their energy absorption and performance. In the present paper, composite materials of glass and epoxy conical shell structures of slipping solid steel cone are studied experimentally. The effect of crush rate and crushing behaviour on failure modes and energy absorption are investigated in details. The specific and volumetric energy absorption capabilities are studied and failure modes for quasi-static analyses were investigated. One type of semi-vertex angle (P) of conical tubes was 10 degrees with stacking sequence of 90/45/-45/90. The composite material specimens were loaded and compressed at various crush speed rates of 5, 10, 15 and 20 mm/min. The results of composite structures are demonstrated and showed that the conical shapes with speed rate of 5 mm/min absorbed high specific energy and displayed more stability in load-stroke curve.

Facile method to synthesis of anatase TiO2 nanorods

A simple wet chemical method was used to synthesise TiO2 nanorods using Titanium isopropoxide (TTIP) as a precursor material. The chemical transformation of TTIP by ethylene glycol (EG) was demonstrated as a strategy for regulating and controlling the shape of formation TiO2 nanorods. The structure of the sample was studied by X-ray diffraction and it revealed that the prepared TiO2 exhibit a pure anatase phase. While the Fourier transform infrared spectroscopy (FTIR) was showing the vibration patterns in the spectrum of the sample. The morphology of sample was studied by scanning electron microscopy (SEM) and it showed that the synthesised TiO2 made of nanorods with length about (698 nm) and a diameter (220 nm).