Synthesis and characterization of ceramic nanocomposite thin films SiO2-NiO for gas sensing

This paper focuses on the preparation and characterization of thin films of SiO2-NiO ceramic nanocomposite. These films were synthesized using the sol-gel method and deposited onto a quartz substrate through spin coating after hydrofluoric acid (HF) treatment for the glass substrate. The films synthesized using 70% SiO2-30% NiO mole ratio. Subsequently calcined at three different temperatures: 500 degrees C, 700 degrees C, and 900 degrees C. The diagram of X-ray diffraction (XRD) revealed the presence of large quantities of semiconductor NiO at 20 = 37.4 degrees, 62.8 degrees, 75.5 degrees, and 79.4 degrees in addition to the presence of SiO2 in the structure, at 20 = 43.3 degrees. The surface properties were studied using scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The test results demonstrated structural and surface properties compatible with the requirements of sensing applications. FT-IR spectra shows absorption bands of Si-O-Si, Ni-O and O-H. This coating has shown good sensitivity and effective response toward ammonia gas under various measurement conditions, including temperatures ranging from 50 to 200 degrees C. The film calcinated at 500 degrees C exhibited high sensitivity to NH3 gas at room temperature due to the presence of hydroxyl groups (OH-), which increased its ability to adsorb the gas. Additionally, the film calcinated at 900 degrees C showed even higher sensitivity compared to the film calcinated at 700 degrees C.