Hollow 3D PANI@PSS-rGO microspheres enabling ultra-sensitive room temperature ammonia gas sensing

Abstract

Designing sensing materials with distinct morphologies remains a key challenge in the development of high-performance gas-sensing devices. In this study, we employed a supramolecular assembly and ice-melting-induced lyophilization (IMIL) technique to synthesize poly (sodium p-styrenesulfonate)-functionalized reduced graphene oxide (PSS-rGO) microspheres. We then used in situ chemical oxidation polymerization to create a hollow three-dimensional (3D) polyaniline-decorated PSS-rGO microspheres (PANI@PSS-rGO) and conducted a trace analysis of ammonia (NH₃) at room temperature. The PANI was uniformly decorated on the surfaces of the PSS-rGO microspheres, and the PANI@PSS-rGO exhibited a hollow microsphere morphology. This structure’s large specific surface area provided sufficient adsorption sites and enabled fast multichannel charge transfer. The hollow 3D PANI@PSS-rGO composite had ultra-high sensitivity of 7.06% / ppm at high concentrations and 55.86% / ppm at low concentrations, as well as short response and recovery times of 9 and 120 s, respectively. We attributed the good selectivity, repeatability, and long-term stability of the PANI@PSS-rGO composite to the significant synergistic effect of the PANI and the PSS-rGO. We determined a promising route to room-temperature gas sensors for ultrasensitive trace analysis of NH₃, which is enabled by this 3D framework.