Fuel cells are one of the most efficient and effective solutions to environmental problems and high energy demand. They are devices which change chemical energy into electrochemical energy, allowing much higher efficiency than conventional thermomechanical conversion methods. Lanthanum Strontium Cobalt Ferrite (LSCF) perovskites have been widely studied for application as cathodes in solid oxide fuel cells (SOFC) due to their high electrical conductivity, high thermal and chemical stability, low difference in thermal expansion coefficient, and physico-chemical compatibility with the other cells components. The aim of this work was to synthesize perovskitas type La0.7Sr0.3Co0.5Fe0.5O3 by sol-gel method and evaluate the potential for application as a cathode for fuel cell. The results obtained by X-ray powder diffraction (XRD) indicate that the sol-gel method calcined at 900ºC obtained an amount of the perovskite phase above 95%. The Field Emission Gun-Scanning Electron Microscope (FEG-SEM) images of LSCF film produced with 4 layers showed a better quality. Thus, the results obtained by XRD and FEG-SEM, indicate that the sol-gel method calcined at 900ºC has a potential application as cathode in solid oxide fuel cells.

This paper presents the application of Design of Experiments (DOE) to an alkaline treatment in mordenite zeolite, in order to identify the optimum settings of the variables (temperature and concentration of NaOH) that promote greater desilication. Samples of commercial mordenite with Si / Al ratio = 9 have been treated with aqueuos NaOH solution of various concentration (0,1;0,5;1,0) and temperature (30,50,70°C). Statistical analysis was carried out based on a 22 factorial design with center point replicates. Seven experiments were executed and the data of Si/Al ratio obtained. The resulting samples were characterized by x-ray difraction (XRD) and energy dispersive x-ray (EDX), to identify the structures and crystalline phases, and to determine the percentages of silicon and aluminum, respectively. In all samples, a decrease in the Si / Al ratio was observed, keeping the crystalline structure. The treatment was most effective, especially, at high temperature and NaOH concentration (experiment 4). DOE was shown to be a powerful techinique for the study of the variables, allowing determining which variables and value ranges have more influence on response, enabling optimization.