Room temperature solid-state synthesis of mesoporous BiOI nanoflakes for the application of chemiresistive gas sensors

In recent years, the fabrication of mesoporous nanostructures through low-cost synthesis methods and their utilization as potential sensing elements has fascinated remarkable attention in the field of chemiresistive-type of gas sensors. In this regard, a simple room temperature solid-state reaction approach towards bismuth oxyiodide nanoflakes (BiOI NFs) for the application of C₂H₅OH gas sensors is described herein. The crystal structure, surface morphology, elemental composition, and surface area characteristics of as-synthesized BiOI are studied by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, Raman/FTIR spectroscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption/desorption isotherms, respectively. Structural, elemental, and morphological investigation supports to tetragonal configuration of solid-state mediated BiOI together with irregular-shaped nanoflakes-type surface morphology. Surface area analysis confirmed that the BiOI NFs are mesoporous in character with a specific surface area of 17.8510 m²/g. Gas sensing results demonstrated that the as-fabricated BiOI NFs sensors are responsive towards C₂H₅OH @265 °C with good response reproducibility/stability. BiOI NFs sensor exhibit maximum response of 27% towards 1000 ppm C₂H₅OH @265 °C. The effect of working temperature and various C₂H₅OH concentrations (10–1000 ppm) on the response performance of BiOI NFs sensor was carried out thoroughly and described. Additionally, a solid-state reaction mechanism and plausible C₂H₅OH gas sensing mechanism of BiOI NFs is discussed. The proposed low-cost room temperature solid-state reaction method presents a stimulating way for the rapid synthesis of mesoporous nanopowders for the application of chemiresistive-type of gas sensors.