Nano titania loaded mesoporous silica: Preparation and application as high performance humidity sensor

Abstract

Relative humidity (RH) sensing response was evaluated using TiO2 supported mesoporous SBA-15 at room temperature in the 11–98 RH% range. The TiO2/SBA-15 hybrid nanocomposites were prepared by wet impregnation and direct loading of titanium species in mesoporous silica, SBA-15 under extreme acidic conditions. Humidity response of the nanocomposite sensor, including linearity, hysteresis, response/recovery time and stability, were investigated by exposing sensors to humid environments in wide range of 11–98 RH% at 25°C. It was found that 10wt% TiO2 loaded in SBA-15 nanocomposite produced by direct synthesis method exhibits improved sensing response toward RH change, along with excellent linearity, fast response/recovery time, excellent repeatability, negligible hysteresis and outstanding stability. The complex impedance spectra of the sensor at different RHs were analyzed to explore the humidity sensing mechanism. The investigation of humidity sensing characteristics of TiO2/SBA-15 nanocomposite indicates that the direct synthesis of mesoporous hybrid material can be used for the fabrication of high performance RH sensors.