High response and low concentration hydrogen gas sensing properties using hollow ZnO particles transformed from polystyrene@ZnO core-shell structures

Abstract

High quality, closely packed nanorods (NRs) textured ZnO hollow particles were prepared via thermal treatment of polystyrene@ZnO core-shell structures at 300 °C. Polystyrene@ZnO core-shell structures were synthesized using a chemical route. These hollow ZnO particles were investigated for hydrogen gas sensing properties. Morphological properties were studied using field emission scanning electron microscope (FE-SEM). Structural parameters and molecular fingerprint confirmation were carried out by x-ray diffraction (XRD) and Raman analysis respectively. The elemental compositions and atomic species of sensor materials were studied using energy dispersive spectrometer (EDS) analysis and x-ray photoelectron spectroscopy (XPS) spectra respectively. The study of atomic planar arrangements and crystalline nature were examined by using a high-resolution transmission electron microscope (HR-TEM) micrograph and selected area electron diffraction (SAED) pattern respectively. Hollow ZnO particles sensor was revealed remarkable selectivity towards hydrogen (H2) gas. The lowest H2 detection limit of ZnO sensor was at 2 ppm with the response of 7%, whereas 89% gas response was recorded for 100 ppm at optimized temperature 225 °C with response time 139 s. Gas response as a function of operating temperatures as well as gas concentrations was tested along with good sensor stability. The transient gas response and selectivity studies were carried out and analyzed. ZnO growth and gas sensing mechanisms were elucidated.