Influence of the addition of nano-TiO2 and ZnO on the sensing performance of micro-ZnSnO3 ethanol sensors under UV illumination

Three-dimensional (3D) flower-like micro-ZnSnO3 particles were prepared based on ZnSn(OH)(6) with less corrosion, and a UV-enhanced ethanol-sensing sensor with the micro-ZnSnO3 as gas sensitive material was studied. In order to reduce the operating temperature of the ethanol sensor, nano-TiO2 and ZnO as photosensitive materials were used to decorate micro-ZnSnO3 to improve its UV absorption. Although the content of nano-TiO2 used for decoration is different due to various surface morphology of ZnSnO3, the ethanol sensors with those TiO2@ZnSnO3 composites reach the maximum response at the same temperature of 80 degrees C. In this paper, nano-ZnO as photosensitive material can not significantly reduce the operating temperature of the micro-ZnSnO3 sensors due to poor UV absorption, whereas the co-decoration of both nano-TiO2 and ZnO on micro-ZnSnO3 can make the operating temperature of the sensors with only nano-TiO2 decoration further reduced. The working mechanism of the ethanol sensors composed of photo- and gas-sensitive materials were discussed based on UV-vis absorption spectra and the above experimental results.