Fabrication of hollow porous ZnO@ZnS heterostructures via hydrothermal method and enhanced gas-sensing performance for ethanol

Abstract Heterostructures with great modulation of electron transfer afford a great opportunity for gas-sensing applications. Herein, a hollow porous ZnO@ZnS core-shell structure with high gas-sensing performance has been successfully hydrothermally synthesized. The phase composition and the morphology of the as-prepared products were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and energy dispersive X-ray spectroscopy. The results show that the pure ZnO and the ZnO@ZnS appear a mesoporous structure and a hollow porous structure, respectively. Gas-sensing measurements show that the gas-sensing performance of the ZnO@ZnS based sensor is obviously higher than that of the pure ZnO, and it has a high selectivity, quick response-recovery and stability to ethanol. Its response reaches 114.2 to 100 ppm ethanol, and the response and recovery time is 3 s and 8 s to ethanol, respectively. The gas-sensing enhancement of the ZnO@ZnS can be attributed to the Schottky barrier at the interface of the ZnO@ZnS and the special hollow porous structure. The strategy put forward is generally applicable to design efficient ethanol sensors with optimized sensing performances.