Investigation of the room temperature gas-detecting potential of CeO<inf>2</inf>-doped ZnO at different ratios using clad-modified fiber optic gas sensor

The detection of volatile organic compounds (VOCs) in ambient environments has opened up a new field for the quick, risk-free, and potentially low-cost identification of respiratory illnesses. In this context, CeO2-doped ZnO nanocomposites were produced through the sol–gel technique at various ratios (CeO2:ZnO at 1:4, 4:4, and 4:1, respectively), and their gas-sensing capability was evaluated and shown using a clad-modified fiber optic sensor to study its potential as a VOC detector. The study was based on the concepts of evanescent wave absorption. The modified cladded optical fiber was exposed to ammonia, ethanol, and methanol gas medium in the testing laboratory. At room/chamber temperature, the sensor's sensitivity is tested for various ratios and their spectral response was recorded, and was observed that CeO2-doped ZnO at 4:1 ratio exhibited better sensitivity towards ammonia gas vapor, with a sensitivity of 2.6 counts/10 ppm and a sensitivity percentage of about 26% for the maximum of 100 ppm. Thus, the RT ammonia gas-sensing capability of CeO2-doped ZnO (4:1) is well suited to industrial applications.