In-situ sulfidation of raspberry-like SnS/SnO2 heterostructure for enhanced Cl2 gas sensing performance at near room temperature

Chlorine (Cl 2 ), a toxic and hazardous gas with a pungent odor, has already posed threat to air quality and human health. Therefore, developing chlorine sensors with high response and low power consumption is crucial. In this work, raspberry-like SnO 2 decorated uniformly with SnS nanoparticles was synthesized via a facile solvothermal method followed by an in-situ sulfurization process, which can be used for highly selective and sensitive detection of Cl 2 at 50 °C. The SnS/SnO 2 sensor exhibits ultrahigh response (R g /R a  = 1136) toward 10 ppm Cl 2 at optimal working temperature of 50 °C, achieving low detection limit down to 0.05 pp m (S = 1.52), which is 2.5 times higher than that of pure SnO 2 sensor. Its superior sensing performance can be attributed to the formation of the p-n heterostructure, which accelerates electron transfer within the material. More importantly, the as-prepared SnS/SnO 2 sensor still exhibits effective and stable detection performance toward residual chlorine in daily life, significantly extending its practical applicability and providing valuable reference for developing high-performance near room-temperature gas sensors.