Three-dimensional hierarchical Co3O4 nano/micro-architecture: synthesis and ethanol sensing properties

Abstract

Recently, spinel cobalt oxide (Co₃O₄) nanostructure has received great interest because of its enhanced gas sensing properties and it offers many opportunities in the sensing field. In the research reported in this paper, spinel Co₃O₄ compounds with various morphologies were prepared by a simple solvothermal process and then applied for gas detection. The structure, morphology and surface characteristics of the as-obtained products were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscope, Brunauer–Emmett–Teller and inductively coupled plasma mass spectrometry analysis. These analyses revealed that the morphologies of the Co₃O₄ nanostructures could be accurately controlled by employing different solvents. To highlight their potential application, gas sensors based on the as-synthesized products were fabricated to test their sensing performances. The test data indicated that the needle-shaped Co₃O₄ compounds had a superb kinetic response and excellent selectivity towards some pollutant volatile organic compounds at an operating temperature of 170 °C, especially ethanol. As such, these hierarchical Co₃O₄ needle-shaped microspheres are a promising candidate for a high-performance gas sensing material.