Synthesis of mesoporous SnO2–SiO2 composites and their application as quartz crystal microbalance humidity sensor

In this paper, chemically derived mesoporous SnO2–SiO2 composite was deposited on a transducer of quartz crystal microbalances (QCMs) to construct a humidity sensor for wide range humidity detection. The composite was synthesized through a facile one-pot sol–gel method and characterized by XRD, TEM, EDX, ICP and nitrogen adsorption–desorption test. The humidity sensing characteristics of the QCMs coated with SnO2–SiO2 composites thin film were investigated by exposing the QCMs to various relative humidity (RH) environments at room temperature, including sensitivity and linearity, response and recovery, and humidity-hysteresis. The results exhibit that the sample with a atomic ratio of Sn/Si = 1:1 shows better humidity sensing properties than others within the range of 11–96.1% relative humidity (RH), and the sensor also displays rapid response and recovery about 14 s and 16 s, respectively. The nanocomposite also shows suitable sensitivity and low hysteresis, revealing its great potential in humidity sensors.