Shape-controlled fabrication and enhanced gas sensing properties of uniform sphere-like ZnFe2O4 hierarchical architectures

Spinel-typed ZnFe2O4 nanostructures have attracted much attention owing to their remarkable properties and display promising potential in gas sensors. In this work, spinel ZnFe2O4 compounds with different 3-D sphere-like morphologies, namely faceted microspheres and solid microspheres, were successfully synthesized by employing a facile template-free solvothermal process coupled with a post annealing treatment. The chemical composition, morphology and surface features of the as-obtained products were characterized well by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller analysis technique. Considering the favorable structures of products, gas sensors were fabricated to explore their sensing performance. Impressively, the detailed gas tests indicate that the faceted ZnFe2O4 microspheres have a marked kinetic response speed and fascinating selectivity toward some volatile organic pollutants, especially to ethanol, at operating temperature of 180 degrees C. As such, we conclude that the faceted ZnFe2O4 microspheres will be a promising candidate as a high-performance gas sensing material. (C) 2017 Elsevier B.V. All rights reserved.