Adsorption of ethanol on V2O5 (010) surface for gas-sensing applications: Ab initio investigation

The adsorption of ethanol on V2O5 (010) surface was investigated by means of density functional theory (DFT) with a combined generalized gradient approximation (GGA) plus Hubbard U approach to exploit the potential sensing applications. The adsorption configurations were first constructed by considering different orientations of ethanol molecule to V and O sites on the “Hill”- and “Valley”-like regions of corrugated (010) surface. It is found that ethanol molecule can adsorb on whole surface in multiple stable configurations. Nevertheless the molecular adsorption on the “Hill”-like surface is calculated to occur preferentially, and the single coordinated oxygen on “Hill”-like surface (O1(H)) acting as the most energetically favorable adsorption site shows the strongest adsorption ability to ethanol molecule. Surface adsorption of ethanol tunes the electronic structure of V2O5 and cause an n-doping effect. As a consequence, the Fermi levels shift toward the conductive bond increasing the charge carrier concentration of electrons in adsorbed V2O5. The sensitive electronic structure and the multiple stable configurations to ethanol adsorption highlight the high adsorption activity and then the potential of V2O5 (010) surface applied to high sensitive sensor for ethanol vapor detection. Further Mulliken population and Natural bond orbital (NBO) calculations quantify the electron transfer from the adsorbed ethanol to the surface, and correlates the adsorption ability of surface sites with the charge donation and dispersion.