Synthesis and enhanced gas sensing properties of flower-like ZnO nanorods decorated with discrete CuO nanoparticles

• Flower-like CuO/ZnO NRs were prepared via a two-step synthesis method.
• The samples exhibits the flower-like microstructure assembled with rods.
• Flower-like CuO-decorated ZnO NRs exhibit great gas sensing performance.

Flower-like CuO/ZnO hierarchical structures were prepared via a flexible two-step synthesis method, in which nanorods-assembled flower-like ZnO microstructures with the diameter about 430–1680 nm and the length about 3.6–8.8 μm were prepared in advance through a chemical solution method, and then a frost-like layer of CuO nanoparticles (NPs) decorated on the surface of ZnO nanorods (NRs) via an ionic-layer adsorption and reaction method. Compared with pure ZnO NRs, the flower-like CuO-decorated ZnO NRs show an obvious improvement in gas sensing performance. The gas sensing mechanism of the CuO-decorated ZnO NRs was discussed in relation to the catalytic effect of CuO and the introduction of the p-n junction between CuO and ZnO.