Volatile organic compound sensing properties of MoO3-ZnO core-shell nanorods

MoO3-ZnO core-shell nanorods were synthesized by a simple two-step process. MoO3 nanorods were synthesized by a hydrothermal method, which was followed by atomic layer deposition of a ZnO shell. The phase and crystallinity of the synthesized products were examined by X-ray diffraction, and the morphological features were studied by scanning electron microscopy. Gas sensing tests were performed on both pristine MoO3 nanorods and MoO3-ZnO core-shell nanorods. Sensors containing the pristine MoO3 nanorods and MoO3-ZnO core-shell nanorods showed responses (Ra/Rg where Ra and Rg are the electrical resistances of the sensors in air and the target gas, respectively) of 1.15 and 7.6, respectively, to 200 ppm ethanol at 350 °C. Therefore, the response of the MoO3-ZnO core-shell nanorod sensors to ethanol gas was significantly better than that of pristine MoO3 nanorods. The underlying mechanisms for the enhanced sensing performance are discussed in detail.