Preparation of hierarchical WO3 dendrites and their applications in NO2 sensing

Hierarchical WO3 dendrites were synthesized via low-cost and environmental-friendly solvothermal strategy. Characterization results indicated that WO3 dendrites were composed of several multi-directional dendritic nanosheets. To further understand the formation of WO3 dendrites, time-dependent experiments were carried out and formation mechanism was investigated. Since such dendritic structures rarely occurred in the field of gas sensing, the synthesized WO3 dendrites were subjected to detailed NO2 sensing tests. Results demonstrated that WO3 dendrites based sensors had low detection limit (200 ppb) and fast response and recovery (7 s, 12 s to 5 ppm NO2). Moreover, the sensor was also highly sensitive, selective and stable at low optimal operating temperature of 140 °C.