High-Performance Ammonia Sensing Electrode Based on a Graphene/Porphyrin–Polyaniline Nanocomposite Material

In view of the hazards and special use value of ammonia (NH3), the development of various types of sensors sensitive to NH3 is one of the hot spots in today’s research. Although the conductive polymer polyaniline (PANI) can detect NH3 at room temperature, it suffers from a series of drawbacks such as low response value, poor selectivity, and long response time. In this study, a graphene/tetraaminophenylporphyrin-PANI (Gr/TAPP-PANI) nanocomposite (GT-P) was prepared by chemical synthesis, and a GT-P NH3 sensing electrode was constructed by drop-casting deposition. The NH3 sensing performance of the GT-P sensing electrode was significantly enhanced by optimizing the mass ratio of TAPP to Gr (2:1). At room temperature, the GT-P sensing electrode showed good response to NH3 with a lower detection limit of 1.99 ppm, high selectivity, and excellent sensing stability. Gr accelerates the electron transfer while π–π stacking with TAPP exposes a larger active center area of TAPP, resulting in the excellent ammonia-sensitive performance of the GT-P sensing electrode. This study provides a strategy for the development of high-performance flexible NH3 sensors, which has broad application prospects in the fields of environmental monitoring and wearable electronics.