Tailored coral-like polyaniline nanorods for trace detection and self-cleaning NH3 sensor at room temperature

Polyaniline (PANI) is one of the most potential materials as ammonia (NH 3 ) gas sensors owing to its reversible protonation and deprotonation nature. However, the detection limit and reversibility of pristine PANI nanomaterials need to be further improved to meet the requirements for high performance sensors under the premise of lower energy consumption and safety conditions in various fields. A trace sensor for NH 3 based on coral-like pristine PANI nanorods was successfully tailored via modified chemical oxidation polymerization. The distinctive coral-like structure of PANI nanorods facilitates the generation of more reactive active sites and interconnected carrier transport channels, which contribute to the performance of the sensor. The PANI sensor exhibits a sub-ppm detection limit (36 ppb) for NH 3 at 24 ℃, in addition to a favorable selectivity and excellent long-term stability properties. Furthermore, it was observed that the application of high relative humidity treatment facilitated the removal of the ammonium salts that had accumulated on the surface of the reacted PANI sensors, thereby restoring the fixed resistance to its initial value. The feasibility of the application of this sensor was demonstrated through monitoring the spoilage of fresh shrimp by means of an integrated circuit system. The findings demonstrated that the synthesized pristine PANI sensor exhibited notable advantages, rendering it a viable option for practical applications in the detection of NH 3 .