Fast response of sprayed vanadium pentoxide (V₂O₅) nanorods towards nitrogen dioxide (NO₂) gas detection

Highlights: • Effect of solution concentration on physicochemical properties of sprayed V₂O₅ nanorods is studied. • Good response and short response-recovery times of V₂O₅ nanorods towards NO₂ gas show it is potential material for fabrication of NO₂ sensor. • The chemisorption mechanism of NO₂ gas on the V₂O₅ nanorods is discussed. - Abstract: The V₂O₅ nanorods have been successfully spray deposited at optimized substrate temperature of 400 °C onto the glass substrates using vanadium trichloride (VCl₃) solution of different concentrations. The effect of solution concentration on the physicochemical and NO₂ gas sensing properties of sprayed V₂O₅ nanorods is studied at different operating temperatures and gas concentrations. The XRD study reveals the formation of V₂O₅ having an orthorhombic symmetry. The FE-SEM micrographs show the nanorods-like morphology of V₂O₅. The AFM micrographs exhibit a well covered granular surface topography. For direct allowed transition, the band gap energy values are found to be decreased from 2.45 eV to 2.42 eV. The nanorods deposited with 30 mM solution concentration shows the maximum response of 24.2% for 100 ppm NO₂ gas concentration at an operating temperature of 200 °C with response and recovery times of 13 s and 140 s, respectively. Finally, the chemisorption mechanism of NO₂ gas on the V₂O₅ nanorods is discussed.