Microwave hydrothermal synthesis and gas sensing application of porous ZnO core-shell microstructures

A ZnO core-shell structure with a movable core inside a hollow shell has been rapidly prepared by an efficient microwave hydrothermal method without any template. The synthesis was performed in an aqueous solution using zinc acetate dihydrate as the precursor. The observations of field emission electron microscopy and transmission electron microscopy showed that these ZnO core-shell structures were composed of numerous primary particles with size of tens of nanometers. A series of time-dependent experiments were carried out in order to have a closer inspection of the evolution processes of such structures. When evaluated as a sensing material for gas sensors, the as-synthesized ZnO core-shell structures displayed a high response towards ethanol and good response-recovery properties.