Three-dimensional porous carbon framework coated with polyaniline for highly stable and selective ammonia sensing

Abstract

Ammonia (NH3) sensing for environmental pollution monitoring is simultaneously required high selectivity against interfering gases, long-term stability with humidity tolerance and low detection limit, which needs further exploring. Here, the compositions of three-dimensional (3D) porous carbon framework (C-FW) coated with polyaniline (PANI@3D C-FW CPs) have been developed for highly selective and stable NH3 detection, which have been firstly prepared 3D C-FW via freezing/drying, and have been then in-situ coated with PANI. As-synthesized PANI@3D C-FW CPs present 3D porous architectures with rough surface. Beneficially, the PANI@3D C-FW CPs show a distinguished selectivity to NH3 against other interfering gases and possess 100 ppb-concentration detection limit at room temperature (∼25 °C), respectively. Remarkably, the PANI@3D C-FW CPs sensor prototypes show outstanding cycling stability to 10 ppm NH3, and 249-day long stability. Theoretically, such outstanding NH3 sensing performance might be attributed to the unique deprotonation/protonation process of PANI molecules layer and the abundant adsorption sites of 3D porous framework structure. Practically, simulation to detect NH3 using as-prepared PANI@3D C-FW CPs has been conducted with reliable sensing response.