Sulfur dioxide gas sensor based on vanadium oxide doped TiO₂ nanopaper

Abstract The gas sensor based on TiO 2 nanomaterials is promising for both industry and daily life because of its simple fabrication, low cost, high sensitivity, and easy application to micro-devices. However, its selectivity is relatively low and strongly influenced by the environment, thus limiting its practical application. In this work, we prepared TiO 2 nanopaper by methods of hydrothermal synthesis and conventional paper preparation. To improve the selectivity, we added V 2 O 5 by immersing the as-prepared nanopaper in an ammonium metavanadate (NH 4 VO 3 ) solution evenly dispersed in ethanol. Nanopaper is a random array of long nanowires and nanofibers, which retains its shape and structure at high temperature, unlike pure nanowires, due to its high porosity and mechanical stability. V 2 O 5 leads to a selective sensing performance with high catalytic activity for SO 2 gas. The surface structure of the sensing material and its porosity were characterized by SEM, XRD, XPS. The improved sensing material exhibited a high response of about 22.6 for 100 ppm SO 2 and a fast response and recovery of 9 s and 14 s, respectively. It also exhibited good reproducibility and selectivity in other interfering gases. Furthermore, the long-term sensing performance in the atmospheric environment was maintained for about 50 days.