Detection of hydrogen sulfide using polyaniline incorporated with graphene oxide aerogel

This paper presents the fabrication of polyaniline and graphene oxide aerogel composite (PGA) thin film-based sensors for H2S gas sensing application. The optical and morphological properties of these composite films were characterised correspondingly by UV-visible spectroscopy and scanning electron microscopy. To prepare the gas sensors, thin films of PANI and PGA composites were deposited onto interdigitated electrodes by spin coating method. The response of these sensors towards H2S gas was evaluated by monitoring the change in electrical conductivity at room temperature under two relative humidity values of 60% RH and 80% RH. The PGA composite thin film-based gas sensors showed a higher response compared with the pure PANI-based sensor. The gas sensor made of PGA-3 showed a good response of 3.87 in 67 s (60% RH), which is 4.6 times higher than that of pure PANI and 2.5 times higher than that of PGA-1 at 1 ppm. The first-principles simulations were carried out to investigate the H2S sensing mechanism of PGA heterostructure. The adsorption of H2S at different locations of pure PANI and PGA composites was analysed. The band gap for PGA showed more significant change after adsorption than that of pure PANI, which indicated the higher sensitivity for detecting H2S.