Solvothermal synthesis of ZnO spherical particles and VOC sensor application

Abstract

We synthesized micrometer-sized ZnO spherical particles solvothermally from the solutions of zinc acetate anhydride, hexamethylenetetramine (HMT), ethylene glycol (EG) and water, and examined the gas sensing properties. The spherical powders were composed of nano particles, which were radially aligned along the c-axis. We obtained particles with smaller crystallites under conditions of higher EG concentrations and shorter reaction period. Spherical powder made of crystallites of 3–5 nm was precipitated in the 95 vol %-EG solvent by heating at 120°C for 4 h. The ZnO powder annealed at 450°C worked as a gas sensor device for volatile organic compounds (VOC) gases. The sensitivity was the best in the case of ethanol gas at 350°C.