Preparation and gas sensing properties of flower-like WO3 hierarchical architecture

• Hierarchical flower-like WO3 assembled with ultrathin nanosheets has been synthesized through simple method.
• The thickness of the nanosheets is only about 8.7 nm.
• The response and recovery times of the sample sensor to ethanol are only 5–7 s and 6–9 s.
• A possible formation mechanism has been proposed.

Flower-like WO3 hierarchical architecture has been successfully synthesized through a facile hydrothermal method. The morphology and structure were investigated via X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The results indicated that the flower-like WO3 were self-assembled by many ultrathin petal-like nanosheets with thickness of several nanometers. A possible formation mechanism of 3D hierarchical architecture was proposed on basis of time dependent experiments. In addition, the well-defined WO3 hierarchical architectures exhibited high response and good selectivity to ethanol at 300 °C with fast response (5–7 s) and recovery (6–9 s) properties, which might substantially benefit from their layer-by-layer ultrathin petal structure.