Polyaniline composited with rGO wrapped-SiO₂ microsphere ammonia sensor with fast response/recovery and high sensitivity for pig healthy breeding

Ammonia detection is important in pig healthy breeding due to its big threat to pig health, and it is still a challenge to detect ammonia rapidly and sensitively. Therefore, an ammonia sensor based on polyaniline composited with reduced graphene oxide wrapped-silicon dioxide microsphere (PANI@rGO@SiO2) is proposed. Firstly, the sensor has fast response/recovery characteristic and the response/recovery time is only 1.09/1.81 s, while its sensing response to 100 ppm ammonia can reach 211%. The supporting effect of SiO2 microsphere can inhibit the stacking of rGO and agglomeration of PANI, providing more adsorption and desorption paths for ammonia. Secondly, the sensor shows high sensitivity of 3.85% ppm-1 in 1-50 ppm ammonia range. The enhanced protonation, high specific surface area and synergistic effect of PANI@rGO@SiO2 can improve its sensitivity. Besides, the sensor has good repeatability, stability and selectivity. As a result, the sensor is used to detect the ammonia released from pig manures and its accuracy is verified by comparing with the commercial detector. Finally, based on the fast response and high sensitivity of the sensor, it realizes the real-time ammonia detection and timely warning in pig house which can provide a reliable method for pig healthy breeding application.