Vanadium Pentoxide Nanobelt For Gas-sensing Applications: Experimental And First-principles Study

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 nanobeltswere experimentally preparedby an ethylenediaminetetraacetic acid?EDTA?-medicated hydrothermal method followed by a mild annealing at 350?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?.The response of V₂O₅ nanobelts gas sensor to 3 ppm ethanol is 1.47,which is much lower than the limit?200 ppm?for the detection of the ethanol gas in the medical field.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+U?calculation.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 the molecular adsorption on the“Hill”-like surface is calculated to occur preferentially,and the single coordinated oxygen on“Hill”-like surface(O_1?H?)acting as the most energetically favorable adsorption site shows the strongest adsorption ability to ethanol molecule.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 V₂O₅nanobelt is proposed based on the geometrical calculation for adsorption configuration.