Thermoelectrical properties of Ca3Co4O9 doped with molybdenum

Reference	Presenter	Authors (Institution)	Abstract
06-120	Everson Junio Ferreira	Ferreira, E.J.(Universidade Federal de Itajubá); Filho, F.M.(Universidade Federal de Itajubá);	Thermoelectric materials are formidable devices that allows the direct conversion of heat into electricity. There are several heat sources worldwide being wasted with high potential to various applications. Therefore, these thermoelectric materials are an option to consume this renewable energy for electricity generation. The first thermoelectric devices were metal alloys based in lead (Hg) and tellurium (Te), which presented low chemical and structural stability over high temperatures, beyond with their toxicity. In this context, researchers proposed the replacement of this alloys with ceramic materials. Their main property are great heat resistance and chemical and structural stability. The Figure of merit (ZT) are the values that characterize the performance of the thermoelectric materials. The ZT is a function of Seebeck coefficient, thermal and electrical conductivity. Thus, the aim of this study was to prepare, characterize and evaluate the thermoelectric properties of Ca3Co4O9 doped with 2,4,6,8,10% of molybdenum. The Ca3Co4O9 doped with molybdenum, obtained by the solid-state reaction were thermally characterized by thermogravimetric (TG) and dilatometry. Furthermore, they were structurally characterized by X-ray diffraction (XRD) and infrared with Fourier transform (FTIR). The morphological characterization was obtained by a scanning electron microscopy (SEM). The thermoelectrical properties of Ca3Co4O9 was evaluated by a precision multimeter coupled to an electrical oven. The XRD analysis revealed structural organization at long range, while FTIR revealed short range order for all samples. The SEM analyzes showed the contour formation of grains sintered at 1323K and 1523ºK. References: Journal and Alloys and Compounds. 2009, 484, 246–248.; Renewable and Sustainable Energy Reviews. 2016, 64, 635–659.; Ceramics International. 2016, 42, 9482-9487.
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