Phase tuned synthesis of titanium dioxide nanoparticles for room temperature enhanced ammonia detection

Synthesis of titanium dioxide nanoparticles is gaining more importance in the field of nanotechnology due to their application in the gas/vapor sensing field. The present study deals with the synthesis of titanium dioxide nanoparticles from titanium isopropoxide solution using various ionic liquids as phase tuning agents. XRD results revealed the crystalline nature and presence of anatase and rutile phases of synthesized titanium dioxide nanoparticles. The shape and size of the particles were analyzed using TEM and SEM images, which indicated their morphology. The adhesion of dip-coated thin films was obtained from contact angle measurements and correlated with surface roughness. The gas sensing ability of the synthesized titanium dioxide nanoparticles was tested by checking the level of chemisorption and measuring the change in resistance of the samples in the presence and absence of gas inside an airtight chamber and plotting it as a function of time. The sensing studies performed on the samples showed that the TiO2 samples with ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate [EMIM.PF6], with the highest anatase phase percentage, displayed the best ammonia sensing. The results suggest that the sol-gel prepared TiO2 acts as an excellent gas sensor and on adding ionic liquid, the performance is further enhanced.