Chemical-resistant ammonia sensor based on polyaniline/CuO nanoparticles supported on three-dimensional nitrogen-doped graphene-based framework nanocomposites.

A novel ammonia (NH3) chemical sensor is presented with ultra-high response, good selectivity, fast response, and long-term stability using detecting layer of polyaniline/cupric oxide nanoparticles supported on three-dimensional nitrogen-doped graphene-based frameworks (PANI/CuO@3D-NGF) nanocomposite. The NH3 gas sensing response of the PANI/CuO@3D-NGF nanocomposite was studied by resistivity method in low concentration range of 50 ppb-100 ppm at room temperature. The PANI/CuO@3D-NGF nanocomposite was prepared through in situ polymerization of PANI on the CuO@3D-NGF with a high surface area. Morphological and structural analysis revealed that the ultrathin 3D interconnected graphene substrate maximizes the surface area. It is also shown that the CuO nanoparticles offer active adsorption sites for free NH3 molecule. The PANI/CuO@3D-NGF nanocomposite gas sensor shows the response of 930% to 100 ppm NH3 with an outstanding low detection limit of 50 ppb and an average response time of 30 s at room temperature. The excellent sensing performance of the PANI/CuO@3D-NGF nanocomposite was attributed to 3D interconnected porous structure, remarkable enhancement of charge carriers as a result of CuO@3D-NGF, and modified π-interactions between molecules. Graphical abstract.