Effect of (100) and (001) Hexagonal WO3 Faceting on Isoprene and Acetone Gas Selectivity

The hexagonal WO3 polymorph, h-WO3, has attracted attention due to its interatomic channels, allowing for a greater degree of intercalation compared to other WO3 polymorphs. Our research group has previously demonstrated h-WO3 to be a highly sensitive gas sensing material for a flu biomarker, isoprene. In this work, the gas sensing performance of this polymorph has been further investigated in two distinct configurations of the material produced by different processing routes. The first sample was synthesized using Na2WO4 center dot 2H(2)O and showed (100) faceting. The second sample was synthesized using WCl6 and showed (001) faceting. The gas sensing response of the nanostructured films deposited using the (100) textured h-WO3 sample 1 had a higher response to acetone at 350 degrees C. The (001) textured h-WO3 sample 2 favored isoprene at 350 degrees C. The selectivity of the latter to isoprene is explained in terms of the dangling bonds present on the (001) facets. The tungsten and oxygen dangling bonds present on the (001) plane favor the adsorption of the isoprene molecule over that of the acetone molecule due to the oxygen containing dipole present in the acetone molecule.

Automated summary

This research investigated the gas sensing performance of two different configurations of the h-WO3 polymorph produced by different processing routes, showing that the (100) textured sample had a higher response to acetone, while the (001) textured sample favored isoprene. The selectivity of the latter to isoprene is explained in terms of the dangling bonds present on the (001) facets.