Role of chromium in tungsten oxide (WO₃) by microwave irradiation technique for sensor applications

Hydrated tungsten oxide (WO₃·H₂O)-based nanoparticles were synthesized using a simple and inexpensive facile microwave irradiation process, by doping chromium (2 wt%, 3 wt%, 5 wt% and 7 wt%) at 2.45 GHz with the power of 180 W for 10 min for gas sensor application. The resultant products were annealed at 600 °C at the ambient atmosphere in order to improve the crystallinity and to remove the impurities. The products were characterized by using powder XRD which confirmed the formation of orthorhombic and monoclinic structure of both as-prepared and annealed samples, respectively. Atomic force microscope shows the role of chromium in determining the surface morphology of the resultant products at microscopic level, Fourier transform infrared spectroscopic analysis confirmed the presence of essential functional groups formed through chemical bonds of the end products, room temperature UV–VIS DRS studies showed the optical behavior of the samples through emissions and band gap energy of the respective materials. Cyclic voltammetry study confirmed the suitability of the prepared chromium-doped tungsten oxide (WO₃) materials through electrochemical property for photocatalytic and sensor applications.