Highly Sensitive and Selective Room Temperature Ammonia Gas Sensor by Novel MoS 2 /Ce 2 Sn 2 O 7 Heterojunction

In this study, we report the synthesis of a MoS2/Ce2Sn2O7composite via a simple hydrothermal method. The selectivity of the as-fabricated sensors was systematically evaluated against a range of volatile organic compounds, including ethanol, acetone, methanol, n-butanol, isopropanol, and triethanolamine. Notably, the MoS2/Ce2Sn2O7heterojunction exhibited superior selectivity for NH3gas at room temperature, with the MoCe3 sample showing an impressive response of 87.3% to 100 ppm of NH3. Furthermore, the MoCe3 sensor displayed a rapid response time of 40 s and an ultra-low detection limit of 50 ppt. The sensors demonstrated excellent repeatability, stability, and humidity resistance when exposed to NH3, with the MoCe3 sensor particularly excelling at lower concentrations at room temperature. The MoCe3 sample also exhibited low activation energy (5 kJ/mol) and enhanced surface band bending compared to other sensors. The gas adsorption/desorption behaviors and the underlying gas sensing mechanisms were systematically explored, highlighting the transition between n-type and p-type phases. The dual-mode sensing capability of the MoS2/Ce2Sn2O7composite, operational at both room and lower temperatures, opens up diverse applications ranging from environmental monitoring to industrial safety.