Synthesis and Characterisation of PANI/GNS and PANI/GNS/TiO2 Nanocomposites for Room Temperature LPG Gas Sensing Application

Pure polyaniline (PANI), PANI/GNS (1%), and PANI/GNS (2%)/TiO2 (20%) were synthesised by the situ chemical oxidation polymerisation method. Titanium dioxide (TiO2) was synthesised using the sol-gel method and graphene (GNS) functionalized by acidic treatment. The XRD, FTIR, and SEM characterization for structural, functional, and morphological investigations has been carried out. X-ray diffraction of nanocomposite materials shows the highly crystalline nature of synthesized material. FTIR analysis revealed the existence of a functional group in nanocomposite materials. SEM analysis shows highly porous nanocomposite materials are formed, that exhibit a lack of agglomeration with uniform distribution of GNS, and TiO2 nanoparticles within the PANI matrix. The resistance change response of synthesised material toward LPG was measured at low and high temperatures at 250 parts per million (ppm), 500 ppm, and 1000 ppm of LPG gas, which determined the characteristics like sensitivity, response, and recovery time of the nanocomposite material. Sensitivity shows that nanocomposite material is highly sensitive towards LPG nearly at 37 °C. In ternary nanocomposite, the response time and recovery time are faster as compared to binary nanocomposite material. The response time of the ternary nanocomposite is 16 seconds and the recovery time is 83 seconds. Study shows that PANI/GNS (2%)/TiO2 (20%) nanocomposite material shows better sensitivity, response and recovery time as compared to PANI/GNS (1%) nanocomposite material towards the higher concentration of LPG gas.