Ultrathin vanadium pentoxide nanobelt for ethanol-sensing applications: Experimental and ab initio study

Highlights: • Ultrathin V₂O₅ nanobelts were prepared by an (EDTA)-medicated hydrothermal method. • V₂O₅ nanobelts show high sensitive to ethanol gas with several ppm level at 250 °C. • Ethanol adsorbed on V₂O₅ naobelt was investigated by ab initio calculations. • Sensing mechanism is related with electronic structure and electron redistribution. • Adsorbate ethanol is oxidized to ethanal on the V₂O₅ nanobelt surface. In this work, a combined experimental and theoretical study on ultrathin nanobelts of vanadium pentoxide (V₂O₅) for ethanol-sensing applications is preformed. The ultrathin V₂O₅ nanobelts were experimentally prepared by an ethylenediaminetetraacetic acid (EDTA)-medicated hydrothermal method followed by a mild annealing at 350 °C in air. The chelating and capping effect of EDTA facilitate the one-dimensional (1D) preferential growth of ultrathin nanobelts. Gas-sensing measurement reveals that the as-synthesized ultrathin V₂O₅ nanobelts are highly sensitive to ethanol gas with several ppm level at operating temperature of 250 °C. Based on the structural characterization of experimental sample, the nanobelt model was constructed and the surface adsorption of ethanol molecule was investigated by density functional theory (DFT) calculation. It is found that surface adsorption of ethanol tunes the electronic structure of V₂O₅ nanobelt considerably and cause an n-doping effect. Further atomic Mulliken charge population analysis reveals quantitatively the donation of electrons from the adsorbed ethanol to the surface. The calculated electronic properties are correlated to the experimental measurement of sensing response. Meanwhile the possible adsorption reaction of ethanol on V₂O₅ nanobelt is proposed based on the geometrical calculation for adsorption configuration.