Room-temperature PANI/SnS 2 chemiresistive sensor for real-time ammonia volatilization monitoring
Zhemin Jia, Yuru Wang, Chen Wang, David Hui, Rositsa Petkova-Slipets, Zhenyu WangAbstract
Ammonia (NH 3 ) volatilization is a major pathway of reactive nitrogen loss, making accurate and real-time NH 3 monitoring essential for improving nitrogen-use efficiency and mitigating environmental impacts. Herein, a room-temperature chemiresistive NH 3 sensor based on a PANI/SnS 2 p–n heterojunction composite is developed for real-time ammonia monitoring. The composite was synthesized via in situ chemical oxidative polymerization and deposited onto flexible Au interdigital electrodes. Structural characterization confirms the successful integration of PANI and SnS 2 and the formation of closely contacted heterojunction interfaces. The optimized composite exhibits a response of 959.7 % toward 100 ppm NH 3 and a sensitivity of 9.85 % ppm −1 at room temperature. In addition, the sensor demonstrated stable sensing performance over a 10-day laboratory test, and excellent selectivity, with negligible responses to common interfering gases. The enhanced sensing performance was attributed to the synergistic effects of the PANI/SnS 2 heterojunction and the NH 3 -induced deprotonation of PANI. Soil volatilization and paddy-field experiments further demonstrated the potential of the sensor for real-time NH 3 monitoring under practical conditions.