Hexamethylenetetramine-mediated TiO₂ films: Facile chemical synthesis strategy and their use in nitrogen dioxide detection

Hexamethylenetetramine (HMT)-mediated rutile and polycrystalline TiO₂ films are directly grown on a glass substrate by a simple chemical wet deposition method at ambient temperature. After confirming the crystallinity, phase-purity and surface morphology, as-grown TiO₂ films were explored for a variety of target gases including nitrogen dioxide, methanol, ethanol and ammonia at different temperatures for confirming the sensor application potential. The TiO₂ film shows a maximum response of 43% to 100 ppm NO₂@180 °C with fast response time of 16 s. In addition, the TiO₂ sensor film has potential to detect concentration of NO₂ as low as 10 ppm.