Double-shell ZnO hollow microspheres prepared by template-free method for ethanol detection

Abstract

Oxide semiconductors with multi-shell hollow architecture are considered favorable candidates as sensing materials for applications in high-performance gas sensors. Herein, the solid, core-shell, and double-shell zinc oxide (ZnO) microspheres were successfully prepared via a facile template-free method. Compared with solid and core-shell spheres, the gas sensor based on double-shell sphere exhibited the highest response to 100 ppm ethanol at 275 °C (∼ 47.4), which was about 4.8-fold higher than that of the solid sphere (∼ 9.8) under the same conditions. Furthermore, the detection limit of the double-shell ZnO microsphere could reach 1 ppm. The enhancement mechanism of the ethanol gas-sensing performance was systematically discussed.