Flower-like WO3 architectures synthesized via a microwave-assisted method and their gas sensing properties

The flower-like WO3 structures were successfully synthesized by a simple calcination of W18O49 nanowires obtained by a microwave-assisted solvothermal method. The as-prepared products were characterized by field emission scanning electron microscopy, X-ray powder diffraction, transmission electron microscopy, and nitrogen adsorption and desorption measurements. The results indicated that the building blocks of the flower-like structure were intercrossing single crystalline WO3 nanorods with diameter of about 30–40 nm and length of about 300–400 nm. The gas sensing properties of as-prepared products to NO2 and acetone were investigated. It was found that the sensor based on WO3 nanostructures exhibited excellent selectivity and high sensitivity toward NO2 at optimum temperature of 90 °C, giving a response of about 42 to 40 ppb NO2. Significantly, operating at 300 °C, the sensorʹs response and recovery time to 100 ppm acetone was only 1 s and 6 s, respectively.