Enhancing gas sensing performances and sensing mechanism at atomic and molecule level of WO3 nanoparticles by hydrogenation

In this work, we successfully developed a strategy for enhancing sensing performances of WO3 nanoparticles by increasing density of the 5-fold coordinated unsaturated W atoms at the surface of WO3 nanoparticles through hydrogenation. Responses of the hydrogenated WO3 nanoparticles sensors towards alcohol, methanol and formaldehyde were found to be 2-3 times higher than that of the WO3 nanoparticles without hydrogenation. We believed that the 5-fold coordinated W atoms function as the sensing reactive sites and elaborated the sensing reaction mechanism at atomic and molecule level. The 5-fold coordinated W atoms can absorb O-2 molecules, create conducive electrons and catalyze the sensing reaction between the chemisorbed oxygen species with the detected gas. The concept of unsaturated 5-fold coordinated W atoms acting as the reaction active sites will be instructive for the in-depth understanding of sensing and other catalytic reaction as well as design of sensing materials and catalysts with outstanding performance. In addition, the hydrogenation activating surface strategy can be applied to increasing sensing and catalytic properties of other metallic oxides.