Metal oxide nanostructures: preparation, characterization and functional applications as chemical sensors

Preparation and characterization of different metal oxide (NiO, WO₃, ZnO, SnO₂ and Nb₂O₅) nanostructures for chemical sensing are presented. p-Type (NiO) and n-type (WO₃, SnO₂, ZnO and Nb₂O₅) metal oxide nanostructures were grown on alumina substrates using evaporation-condensation, thermal oxidation and hydrothermal techniques. Surface morphologies and crystal structures were investigated through scanning electron microscopy and Raman spectroscopy. Furthermore, different batches of sensors have been prepared, and their sensing performances towards carbon monoxide and nitrogen dioxide have been explored. Moreover, metal oxide nanowires have been integrated into an electronic nose and successfully applied to discriminate between drinking and contaminated water.