Porous Hierarchical In2O3 Micro-/Nanostructures: Preparation, Formation Mechanism, and Their Application in Gas Sensors for Noxious Volatile Organic Compound Detection

A porous hierarchical In2O3 micro-/nanostructure was prepared by oxidizing In2S3 precursors for gas sensor applications. The formation mechanism of the porous structure was investigated systemically by means of simultaneous thermogravimetry and differential thermal analysis, conventional X-ray diffraction, and energy-dispersive XRD cooperated with field-emission scanning electronic microscopy observations. In gas-sensing measurements with noxious volatile organic compounds as target gases, the gas sensor based on porous hierarchical In2O3 micro-/nanostructures showed a sensitive performance with a large detecting concentrations range. Besides, the as-fabricated gas sensor also exhibited significant selectivity toward each target gas. Both the sensitivity and the selectivity of the porous hierarchical In2O3 micro-/nanostructure-based gas sensor enable it to be potentially applied for environmental monitoring toward noxious volatile organic compounds. Furthermore, the gas-sensing mechanism was also demonstrated from the kinetic process of gas adsorption-desorption.