Visible light assisted nitrogen dioxide sensing using tungsten oxide - Graphene oxide nanocomposite sensors

Tungsten oxide (WO3) coatings were deposited by solution precursor plasma spray (SPPS) on alumina substrates. In order to enhance the NO2 sensing properties of the pure WO3 coatings at room temperature, illuminating with visible light and formation of p-n heterojunction were used. The SPPS WO3 coatings were modified by immersing them into a synthesized graphene oxide (GO) suspension to obtain the WO3-GO composites. Raman and FTIR results demonstrated that p-n heterojunctions were successfully formed in the WO3-GO composites. The UV-Vis spectra showed that the WO3-GO composites had a longer visible light absorption range compared with the WO3 coatings. The sensors based on the WO3-GO coatings exhibited ultra-high responses to NO2 at room temperature performed under visible light illumination.