MoS ₂ Heterojunction-Based Gas Sensor Platform Enables Real-Time Detection of Sarin at Room Temperature via Strong Adsorption and Enhanced Charge Transfer

Chemical warfare agents (CWAs) are still a serious threat to human safety with high toxicity and ease of preparation. Developing room-temperature sensors to build miniaturized, low-power monitoring networks is an effective approach for achieving early warning of CWAs. However, most existing studies have reported responses to simulants such as dimethyl methylphosphonate (DMMP) at room temperature, but have not validated the detection effect of sarin (GB). Herein, by constructing high-quality MoO2-MoS2 Schottky heterojunctions in situ through a single controllable process step, we constructed a room-temperature semiconductor sensor for efficient detection of GB. Through the specific chemisorption of GB's characteristic P=O group at Lewis acid sites (MoO2) and the efficient regulation of charge transfer at the Schottky heterojunction interface, the synergistic interaction mechanism enables the MoO2-MoS2 heterojunction-based sensor to exhibit fast response time (18 s), high sensitivity (21.2%), and high selectivity toward 200 ppb GB at room temperature, along with an impressive detection limit (4 ppb). In situ characterization and theoretical calculations are combined to elucidate the mechanism for the enhanced response of the MoO2-MoS2 Schottky heterojunction to GB over DMMP. Additionally, real-time and selective distinguishing of mixed GB gases is realized by the dual-channel sensing array integrated with machine learning algorithms. This strategy offers a viable approach for designing room-temperature chemical agent sensing devices.