A Facile Method for the Synthesis of Porous ZnO Hollow Microspheres and Their Gas Sensing Properties for Acetone

In order to enrich the variety of zinc oxide (ZnO), well-defined porous ZnO hollow microspheres (PZHM) by a mass of nanoparticles were successfully synthesized through a simple solvothermal method. Zinc acetate and 1,2-propylene glycol was used as zinc source and solvent respectively to fabricate PZHM without the assistance of any surfactant. Upon changing the amount of zinc acetate and 1,2-propylene glycol, the morphology of the samples could be adjusted. PZHM, with 1–2 μm in diameter and 200–300 nm in wall thickness, were found to be composed of nanoparticles that assembles to form the large surface area and highly porous samples. Gas sensing performances of the ZnO hollow spheres have been investigated, showing high sensitivity (S = 180 at 1000 ppm), low detection limit (1 ppm), fast response/recovery (8/9 s), and very good selectivity.