UV-light activated APTES modified WO3-x nanowires sensitive to ethanol and nitrogen dioxide

Abstract The sensing properties of (3-aminopropyl)triethoxysilane modified tungsten oxide nanowires (APTES@WO3-x) based sensors toward several gases and vapors are reported in this work. The developed sensors show high sensitivity to ethanol and nitrogen dioxide under UV-irradiation at room temperature (24 °C). Gas sensing results demonstrate enhanced sensing properties for the APTES@WO3-x compared to non-modified WO3-x sensors, with the APTES@WO3-x sensors showing approximately 17 and 20 times more sensitivity to ethanol and nitrogen dioxide, respectively, compared to the non-modified WO3-x sensors. The APTES@WO3-x sensors also display improved selectivity to nitrogen dioxide (oxidizing gas) and ethanol (among other reducing gases including acetone, toluene, hydrogen, and carbon monoxide). These results are attributed to the presence of the reactive amino group at the APTES@WO3-x sensors, which facilitates the chemical interaction with nitrogen dioxide and ethanol and the electron transfer towards/from WO3-x under UV-light excitation.