Flower-Like CNTs@MoS ₂ Core–Shell Nanostructure for NH ₃ Gas Sensor at Room Temperature

High Resolution Image Download MS PowerPoint Slide Ammonia (NH 3 ) is a hazardous gas requiring rapid detection at room temperature for practical environmental and agricultural monitoring. Herein, we report a flower-like CNTs@MoS 2 core–shell heterostructure synthesized via a facile hydrothermal process for room-temperature NH 3 sensing. Structural analyses confirm uniform MoS 2 nanosheets anchored on the CNT networks, forming well-defined p–n heterojunction interfaces that facilitate efficient charge transport. This architecture effectively combines the high surface activity and gas adsorption capability of MoS 2 with the superior electrical conductivity of CNTs, promoting rapid charge transfer and enhanced sensing performance. The optimized sensor achieves a high response of 94% toward 500 ppm of NH 3 with rapid response and recovery times of 36 and 68 s, respectively. Additionally, humidity-assisted interfacial charge transfer further improves the sensor response under high relative humidity. Long-term stability tests demonstrate ∼80% response retention after 150 days. This study elucidates the dominant role of MoS 2 and the synergistic charge modulation enabled by CNTs@MoS 2 heterostructures, providing a clear design strategy for high-performance NH 3 gas sensor at room temperature.