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

Abstract

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.