In this study, a new anodized aluminum oxide (AAO) nanostructure membrane was synthesized by anodization process under a constant voltage, in oxalic acid solution that was improved with trace amounts of sulfuric acid at room temperature. The effect of various parameters on the morphology of the synthesized nanostructures such as voltage, electrolyte composition, anodization time and type of stripping solution were investigated. According to the results, corrosion of the walls, size regularity, diameter and number of the pores increased in the presence of sulfuric acid (0.018 mol.L). Nitrogen adsorption-desorption analysis confirmed significant porosity, array and uniformity of the pore size in the synthesized nanoporous membrane. A new modification method was used based on ultrasonic-hydrothermal method to modify the synthesized AAO with FeO/SiO nanoparticles for metals and metalloids removal from aqueous solution. In this method, FeO/SiO nanoparticles were placed very regularly and uniformly on the surface and inside the pores. This modification was confirmed by characterization techniques. The modified AAO@FeO/SiO membrane showed excellent results for removing arsenic from aqueous media.
a b s t r a c tIn this work, attempt is made to development of active non-precious metal catalysts (NPMCs) for the oxygen reduction reaction in polymer electrolyte fuel cells (PEFCs) based on the heat treatment of polyaniline/transition metal/carbon precursors. All the materials have been characterized by X-ray diffraction (XRD) small and wide angle, N 2 adsorptionedesorption isotherms, high-resolution transmission electron microscopy (TEM), Scanning electron microscope (SEM) and X-ray photo-electron spectroscopy (XPS). Moreover for electrochemical evaluation of samples, Rotating Disk electrode (RDE) technique and Fuel Cell test were employed. The results showed that onset potential for the optimized sample is about 0.1 v less than the commercial catalyst whereas exchange current density of the optimized sample (at 0.2 V vs. Reversible Hydrogen Electrode (RHE)) is about 15 mA cm À2 more than platinum electro-catalyst. Finally, the polarization curves for the fabricated membrane electrode assembly (MEAs) with overall catalyst loading of 2 mg cm À2 demonstrated that the optimized catalyst shows suitable performance compared with E-tek commercial platinum sample.
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