Study On QCM Gas Sensor Based On Nano-structured TiO₂

Gas sensors are broadly applied in many fields such as environmental monitoring, industry, national defense and public safety, which have demonstrated a bright future. Along with the improvement of people's life, it is of great practical importance to develop gas sensors which are sensitive, stable, low power, compatible with electronic devices, portable at room temperature. Gas sensors based on quart crystal microbalance(QCM) principle that meet these requirements have drew much attention within research groups in recent years.Phthalic acid esters are a kind of chemical pollutants widespread in the global environment, and dibutyl phthalate(DBP) is representative of these kind of compounds. DBP could disrupt the normal endocrine function in mammals and cause reproduction defects. To detect DBP in low concentration, we studied QCM gas sensors based on nano-structured TiO₂.Combined with QCM principle and signal detection theory, we firstly developed a QCM gas detection platform based on microcontroller. Secondly, we use hydrothermal method to prepare nano-structured TiO₂, and a drop-coating method was used to form the sensing film on the electrode. Then utilizing the home-made gas detection platform, the sensors' performance parameters such as sensitivity, selectivity and stability were investigated. The results showed that at room temperature, the sensor response to DBP had a good linearity in the concentration range from 0.0434ppm to 0.735ppm; Compared with response to ethanol, acetaldehyde, ethylene and acetone, it was obvious that the sensor had a good selectivity to DBP; After 30 days storage, the response to DBP remained 80% of the initial one. At last, effect of the nano structure of sensing film was discussed.