Ammonia Sensor Based on Monoclinic WO3 Nanorods Operating at Room Temperature

The WO
₃
nanorods are prepared via the hydrothermal method in our work. The measured indexes were tested and analyzed meticulously to verify the crystal phase is affected due to its calcinated temperature. Furthermore, the scanning electron microscope (SEM) and the X-ray diffraction (XRD) are used to characterize the different phase WO
₃
. In the light of the results of XRD, the WO
₃
calcined at 400 °C presents hexagonal phase, whereas the WO
₃
annealed at 500 °C and 600 °C exhibits monoclinic. On the basis of SEM, the nanorods are gradually disintegrated with the temperature increase. The monoclinic WO
₃
demonstrated excellent selectivity to ammonia at room temperature. Moreover, it displayed a short response time and fast recovery rate at optimal working temperature.