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Abstract: Monodisperse magnetite nanoparticles coated with organic ligands have been chemically synthesised by using the poliol method. Modifying the synthetic conditions, particle diameter can be tuned from 3.5 to 7.1nm. In order to investigate the critical size effects on the magnetic behavior of the samples, Fe3O4 nanoparticles have been fully characterized by X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, SQUID magnetometry and electron paramagnetic resonance spectroscopy. [Copyright &y& Elsevier]

Abstract: The creation of porous materials with three-dimensional periodicity has been identified as being of potential interest for increasing the overall performance of solid oxide fuel cells (SOFC). In this work, we have investigated the formation of pore systems in the nanometer scale by replicating colloidal templates. Templating methods have been used to prepare iron–nickel-based perovskite Pr0.7Sr0.3Fe0.8Ni0.2O3 material with nanoporous microstructure. Polymethyl methacrylate (PMMA), polystyrene (PS) and polycarboxylate (PC) microspheres with different diameters were used as pore formers. These samples were synthesized and characterized by thermogravimetric analysis, inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction, transmission electron microscopy and field emission scanning electron microscopy. The polarization resistance of the materials was studied by Electrochemical Impedance Spectroscopy. The study demonstrated that templated porosity is maintained and highly influences on the impedance spectroscopic behaviour, being the material synthesized with policarboxylate microspheres the most interesting of the three used templates for SOFC applications. [Copyright &y& Elsevier]