Malik Maaza


2 Microwave Assisted Growth of Varied Phases and Morphologies of Vanadium Oxides Nanostructures: Structural and Optoelectronic Properties

Authors: Mohammed Khenfouch, Malik Maaza, Bakang M. Mothudi, Issam Derkaoui, Izeddine Zorkani, Anouar Jorio


Transition metal oxides nanoparticles with different morphologies have attracted a lot of attention recently owning to their distinctive geometries, and demonstrated promising electrical properties for various applications. In this paper, we discuss the time and annealing effects on the structural and electrical properties of vanadium oxides nanoparticles (VO-NPs) prepared by microwave method. In this sense, transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman Spectroscopy, Ultraviolet-visible absorbance spectra (Uv-Vis) and electrical conductivity were investigated. Hence, the annealing state and the time are two crucial parameters for the improvement of the optoelectronic properties. The use of these nanostructures is promising way for the development of technological applications especially for energy storage devices.

Keywords: Microwave, Electrical Conductivity, optoelectronic properties, Vanadium oxide

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1 Nafion Nanofiber Mat in a Single Fuel Cell Test

Authors: Chijioke Okafor, Malik Maaza, Touhami Mokrani


Proton exchange membrane, PEM was developed and tested for potential application in fuel cell. Nafion was electrospun to nanofiber network with the aid of poly(ethylene oxide), PEO, as a carrier polymer. The matrix polymer was crosslinked with Norland Optical Adhesive 63 under UV after compacting and annealing. The welded nanofiber mat was characterized for morphology, proton conductivity, and methanol permeability, then tested in a single cell test station. The results of the fabricated nanofiber membrane showed a proton conductivity of 0.1 S/cm at 25 oC and higher fiber volume fraction; methanol permeability of 3.6x10^-6 cm2/s and power density of 96.1 and 81.2 mW/cm2 for 5M and 1M methanol concentration respectively.

Keywords: Nanofiber, Fuel Cell, Permeability, nafion

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