Continuous hydrothermal flow-inspired synthesis and ultra-fast ammonia and humidity room-temperature sensor activities of WO<sub>3</sub> nanobricks
Shoyebmohamad F. Shaikh, Balaji G. Ghule, Pritamkumar V. Shinde, Siddheshwar D. Raut, Shyam K. Gore, Mohd Ubaidullah, Rajaram S. Mane, Abdullah M. Al‐Enizi
Abstract
Abstract Mesoporous tungsten oxide nanobricks (WO 3 NBs) are successfully prepared via a simple and cost-effective hydrothermal synthesis method. The as-synthesized WO 3 NBs demonstrate a high sensitivity and selectivity when used for liquid ammonia and humidity sensor activities at room temperature (27 °C). The monoclinic crystal structure has beencorroborated from thex-ray diffraction studies and the specific surface area is estimated to be 38.74 m 2 g −1 . A larger specific surface area has significantly facilitated a fast gas adsorption/desorption process. The WO 3 NBs notably exhibite gas sensitivity and selectivity for volatile organic compounds (VOCs) such as ammonia; however, a moderate performance is displayed with different oxidizing and reducing agents at room-temperature, namely: toluene, methanol, ethanol, and acetone. The sensor has offered a commercial potential with an extremely high response (75%), a 15-day operational stability at 100 ppm concentration of ammonia, and a practically remarkable ultra-high 8/5 s response/recovery time. The WO 3 NBs-based humidity sensor endows a 32% resistance response at 20% relative humidity, with a quick response/recovery time of 10/8 s; which is due to unique surface architecture of these NBs.