Development of Nano-$$\hbox {WO}_{3}$$ Doped with NiO for Wireless Gas Sensors

\(\hbox {WO}_{3}\) doped with NiO nanopowders with different NiO concentrations were prepared by sol–gel technique. The fabrication of the thin films for gas sensors applications was utilized using thermal vacuum evaporation technique. The morphological structure, crystallinity and optical properties of \(\hbox {WO}_{3}\) and NiO-doped \(\hbox {WO}_{3}\) nanopowders were characterized using scanning electron microscopy, X-ray diffraction and UV–Vis spectrophotometer, respectively. The electrical behaviors of the sensors were determined and measured by the two platinum electrodes sensor’s resistance with different gases at various temperatures. The results show that a great response to \(\hbox {CO}_{2}\) gas was 164% at 5% doping ratio which is applicable for all environmental and industrial fields. GSM module by MAX circuit was applied on gas sensor devices to send a wireless message telling that there is a leakage in the area which the sensor installed.