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Secretaria: Aptor 7encontro@sbpmat.org.br |
Materials for a Sustainable Development: The Key Role of Nanostructure Environmental problems are crucial for a future sustainable development. Fossil fuel combustion processes, from where the vast majority of energy is now produced, are the main pollution sources. From one side, the development of cheap methods for air quality control is needed to keep track of pollutants in the atmosphere and of their harmful outcomes. On the other side, reducing pollutant emissions, including greenhouse gases, is needed for compatibility with environment preservation. This can be achieved through the development of new technologies for energy production and storage, but also with control of diffuse vehicle emissions through on-board diagnostic (OBD) systems. For the latter, the development of high-temperature sensors to directly detect pollutants, such as NOx or CO and hydrocarbons, is desired to improve OBD reliability. Among alternative energy production technologies, fuel cells seem to be very promising as electrochemical power sources either for application in portable technology and in electric vehicles (polymer electrolyte membrane fuel cells, PEMFCs), or for stationary energy production (solid oxide fuel cells, SOFCs) [1]. Both technologies are proven but mass diffusion is limited by their high costs. For SOFCs, the present state-of-the-art commercial technology allows operation at 1000°C for cells using yttria-stabilized zirconia (YSZ) as electrolyte. Their operating temperature reduction is pursued to reduce costs and improve lifetime [2]. For PEMFCs, the present technology uses Nafion as the state-of-the-art material for polymeric membrane. Nafion operating temperature cannot overcome 100°C, but for automotive applications working temperatures above this value are needed to use methanol as a fuel, to produce water as vapour, overall to reduce costs. Since the last decade the author is working intensively on nanostructured materials for environment and energy. This talk will highlight the main achievements obtained for: (i) the development of cheap environmental monitoring systems based on chemoresistive gas sensors made of nanostructured semiconducting-oxide thick-films [3-5]; (ii) non-Nernstian high-temperature electrochemical sensors for automotive applications with nanostructured electrodes [6,7]; (iii) nanocomposite and hybrid materials for increasing the PEMFC operating temperature [8-10]; and (iv) nanostructured oxides for intermediate temperature SOFCs [11-14].
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