Easy and Green Route towards Nanostructured ZnO as an Active Sensing Material with Unexpected H 2 S Dosimeter-Type Behaviour

Nanostructured ZnO particles were prepared through a straightforward, quick and low-temperature synthesis route involving coprecipitation of the metal precursor salts with oxalic acid, followed by hydrothermal treatment at 135 or 160 °C. The synthesised nanostructured powders were thoroughly characterised by a wide array of analytical techniques from the morphological (Scanning Electron Microscopy -SEM-, Transmission Electron Microscopy -TEM-, Energy-dispersive X-ray Spectroscopy -EDXS-), structural (Powder X-ray Diffraction -PXRD-, Selected Area Electron Diffraction -SAED-), compositional (X-ray Photoelectron Spectroscopy -XPS-) and physical (thermal stability) point of view. As far as functional applications are concerned, the powders were tested as gas sensor materials for H 2 S detection. Thereby these ZnO particles showed unexpected gas dosimeter behaviour at 150 °C. Based on these observations and on a comparison with literature a new model for the interaction of ZnO nanostructures with H 2 S is proposed.