Interfacial Engineering Facilitates Real-Time Detection of Dual Hazardous Gases at ppb Levels via Single-Step Hydrothermal Nanoarchitectonics of Self-Assembled PbSnS/SnO2 Heterostructures

Next-generation real-time gas sensors are crucial for detecting multiple gases simultaneously with high sensitivity and selectivity. In this study, ternary metal sulfide (PbSnS)-incorporated metal oxide (SnO₂) heterostructures were synthesized via a one-step hydrothermal method. Characterizations such as X-ray diffraction, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy confirmed the successful formation of PbSnS/SnO₂ heterostructures. Subsequently, thin films based on PbSnS/SnO₂ heterostructures were fabricated and employed for the detection of real-time dual hazardous oxidizing gases at room temperature. The sensor response for NO₂ gas was found to be 1.04 at 25 parts per billion (ppb) with a limit of detection (LOD) of 18.17 ppb, while for O₃ gas, the sensor response was 1.03 at 15 ppb with an LOD of 7.34 ppb. Moreover, high selectivity for detecting two oxidizing gases in real time by using differential analysis of the gas sensing curve has been reported. Furthermore, density functional theory calculations corroborated the sensing mechanism, elucidating that the Pb atom in PbSnS/SnO₂ is primarily responsible for the adsorption of NO₂ gas, whereas SnO₂ in PbSnS/SnO₂ is responsible for the adsorption of O₃ gas. These findings demonstrate the potential of PbSnS/SnO₂ heterostructures for advanced gas sensing applications, offering insights into their fundamental sensing mechanisms.