Template-free to fabricate highly sensitive and selective acetone gas sensor based on WO3 microspheres

Abstract

In this paper, we described how WO3 microspheres have been synthesized by a simple hydrothermal treatment from the precursor of Na2WO4 and CO (NH2)2 at 160 °C for 3 h. The sample was characterized by X-ray diffraction (XRD), energy dispersive spectrum (EDS), scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), high resolution transmission electronic microscopy (HRTEM), selected area electron diffraction (SAED), and X-ray photoelectron spectroscopy (XPS). Obtained results indicated that the average diameter of the as-prepared WO3 microspheres is ∼1 μm with orthorhombic phase. The WO3 microspheres are constructed of polycrystalline WO3 nanoparticles. The thickness of the WO3 coating of the gas sensor is ∼2 μm. The WO3-based gas sensor exhibited a good sensitivity and high selectivity to acetone vapor at 200 °C. A possible mechanism for the acetone vapor gas sensing was proposed.