High-sensitivity hydrogen gas sensors based on Pd-decorated nanoporous poly(aniline-co-aniline-2-sulfonic acid): poly(4-styrenesulfonic acid)

We report a novel method for fabricating Pd-decorated nanoporous poly(aniline-co-aniline-2-sulfonic acid): poly(4-styrenesulfonic acid) (P(ANI-co-ASA):PSS) nanostructures and demonstrate their use as sensing elements for hydrogen (H-2) gas sensors. Both co-monomers and PSS provide sufficient -SO3H groups to effectively anchor palladium nanoparticles and lead to enhanced interactions with H-2 gas, while retaining the charge transport properties of the P(ANI-co-ASA): PSS. The pores were 10-30 nm in diameter and were readily formed on the Pd-decorated P(ANI-co-ASA): PSS surfaces by introducing water-soluble porogen agents. The pores enlarged the surface area available for interaction with the H-2 gas molecules, resulting in much higher sensitivity compared with both the non-porous Pd-decorated P(ANI-co-ASA): PSS and the pristine P(ANI-co-ASA): PSS. We achieved a detection limit of 5 ppm for H-2 gas using a conducting polymer at room temperature.