Gas detection is important for controlling industrial, and vehicle emissions, agricultural residues, and environmental control. In last decades, several semiconducting oxides have been used to detect dangerous or toxic gases. The excellent gas sensing performance of these gas sensor devices have observed at high temperatures (~250oC), which forbids the use for the detection of flammable and explosive gases. In this way, ultraviolet light activated gas sensors have been a simple and promising alternative to achieve room temperature sensitivity. Among the semiconductor oxides which exhibit a good performance as gas sensor, the zinc oxide (ZnO) and tin oxide (SnO2) have been highlighted. Nevertheless, their poor selectivity is the main disadvantage for application as gas sensor devices. Recently, heterostructures combining these two semiconductors (ZnO-SnO2) have been studied as an alternative way to enhance the gas sensor performance (sensitivity, selectivity, and stability). However, the controlled and reproductive synthesis of these nanostructured heterostructures has been the main challenge of the researchers. In this project, we proposed a four months internship for the synthesis of ZnO and SnO2 compounds and their ZnO-SnO2 heterostructures via nonaqueous sol-gel route. The samples will be characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Additionally, gas sensing measurements will be performed with and without UV-light radiation using oxidizing and reducing gases. This internship will count on the supervision of Professor Markus Niederberger, chair of the Laboratory of Multifunctional Materials of ETH Zürich.
News published in Agência FAPESP Newsletter about the scholarship: