Selective Methane gas sensing at low temperatures using hydrothermally synthesized V2O5 nanorods

Methane (CH₄) is a flammable greenhouse gas requiring detection at low concentrations under safe and practical conditions. In this study, vanadium pentoxide (V₂O₅) nanorods were synthesized via a simple hydrothermal method and used as the sensing layer in a resistive gas sensor. Structural and morphological analyses confirmed well-crystallized nanorods with favorable surface properties. The sensor’s performance was evaluated across various CH₄ concentrations at room temperature and 50 °C. While it showed limited response and selectivity at room temperature, operation at 50 °C significantly improved both. The sensor detected CH₄ down to 200 ppm, with a maximum response of 23 % at 4000 ppm. It exhibited fast response and recovery, high repeatability, and stable performance over two months. A conductivity transition from n-type to p-type was observed at 50 °C due to CH₄ surface interactions. These findings highlight the promise of V₂O₅ nanostructures for reliable, low-temperature, and selective CH₄ sensing.