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 (R-a/R-g where R-a and R-g 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 degrees 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. (C) 2017 Elsevier B.V. All rights reserved.