Different morphologies of WO3 and their exposed facets-dependent acetone sensing properties

Daisy-like hexagonal WO3 and rose-like monoclinic WO3 hierarchical structures were fabricated via facile hydrothermal technic in this work. The acetone sensing properties of the products were evaluated in detail. The results reveal that the hexagonal daisy-like WO3 sensor exhibits high sensitivity, good selectivity, rapid response/recovery, and remarkable repeatability to acetone (0.2∼200 ppm) at 260 °C. The outstanding sensing performance is attributed to the synergistic effects of the dominant (002) facets and the intracrystalline tunnel structure of hexagonal phase. The morphology formation mechanism and the acetone sensing mechanism are discussed. This work has practical significance for environmental monitoring of acetone as well as for breath diagnosis of diabetes.