Highly sensitive parts per trillion detection of microwave assisted V2O5 nano-flake sensor for hazardous NO2

Abstract

Among few layered metal oxides, one of the most effective metal oxides for detecting NO₂ is vanadium oxide (V₂O₅), which has van der Waals interacted stacked VO₆ octahedral units, multiple oxidation state, less toxicity, abundancy, and Lewis base nature. Hence, microwave assisted V₂O₅ nano-flakes (NFs) were synthesized with active sites and oxygen defects. The activation energy of 741.3 kJ/mol, with surface area of 67.9 m²/g favors more interactive sites for NO₂. For 20 ppm NO₂ at 170 °C, a high response of 152.4 % with an ultra-low LOD of 413 ppt has attained. Further, the sensor demonstrates a long-term stability over 30 days, as well as the stability towards relative humidity and good selectivity towards NO₂ elucidates the potential for NO₂ detection in environmental monitoring applications.