Fabrication of CeO2/ZnCo2O4 n–p heterostructured porous nanotubes via electrospinning technology for enhanced ethanol gas sensing performance

Abstract

Nanocomposite materials with a one-dimensional structure have rapidly developed in recent years. Metal oxides are applied in a wide range of daily applications. In this paper, pure CeO₂ and composite CeO₂/ZnCo₂O₄ nanotubes are successfully synthesized by single capillary electrospinning technology and post heat treatment. The structure and composition of pure CeO₂ and the composite CeO₂/ZnCo₂O₄ nanotubes are confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM) images identify the as-synthesized materials as hollow, mesoporous structures; the long nanotubes of both samples have a diameter around 60 nm, and the composite CeO₂/ZnCo₂O₄ has a high porosity. The surface structure characteristics of these samples are characterized by N₂ absorption–desorption isothermal analysis (Brunauer–Emmett–Teller, BET) and a large surface area is exhibited for the composite CeO₂/ZnCo₂O₄ nanotubes of 80.989 m² g⁻¹. The QR-2 gas sensing system was used to measure the gas sensing properties of the test materials. We show an excellent improvement in the response and selectivity of the n–p heterojunction CeO₂/ZnCo₂O₄ nanotubes in comparison with pure CeO₂ nanotubes to ethanol gas at an optimal temperature of 180 °C. The gas sensing mechanism of the as-obtained materials toward ethanol gas is discussed. This material has promising potential in the gas sensing field.