Synthesis, Characterization and Chemical-Sensor Applications of Zinc Oxide-Graphene Nanocomposite

The proposed study focuses on the development of a gas sensor utilizing a quartz crystal microbalance (QCM) as the sensing platform. The sensor incorporates a nanocomposite of Zinc Oxide (ZnO) and Graphene as the sensitive layer. The synthesis of this nanocomposite involves a chemical method for thin film is deposition on QCM using spray pyrolysis technique. To evaluate the sensor's sensitivity, the frequency shift (∆f) of the coated QCM electrode is monitored when exposed to different gas concentrations such as ethanol, propane, and humidity. The frequency shift serves as an indicator of the gas concentration being detected. The isotherm response characteristics demonstrate good reproducibility and reversibility, suggesting the reliability of the sensor. Several techniques are employed to analyze various aspects of the coated QCM electrodes. Contact angle measurements (CA) are utilized to assess the surface wettability, providing information on how the nanocomposites interacts with the surrounding environment. Chemical compositions of the coated electrodes have been investigated by employing attenuated total reflectance-Fourier transform infrared (ATR- FTIR) spectroscopy. Scanning electron microscopy (SEM) is utilized to study the surface morphology of the coated QCM electrodes, providing detailed information on the structure and topography of the sensor's sensitive layer.