Flower-Like CNTs@MoS₂ Core-Shell Nanostructure for NH₃ Gas Sensor at Room Temperature

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Ammonia (NH3) is a hazardous gas critical for environmental and agricultural monitoring.
• Rapid, room-temperature detection of NH3 is essential for practical applications.
• Existing sensors often face challenges with sensitivity, response time, or stability.

Purpose of the Study:

• To develop a high-performance NH3 gas sensor operating at room temperature.
• To synthesize and characterize a novel CNTs@MoS2 core-shell heterostructure for enhanced gas sensing.
• To investigate the synergistic effects of MoS2 and CNTs in NH3 detection.

Main Methods:

• Facile hydrothermal synthesis of flower-like CNTs@MoS2 core-shell heterostructures.
• Structural analysis using electron microscopy and spectroscopy.
• Fabrication and testing of a gas sensor based on the synthesized material.
• Evaluation of sensing performance, including response, selectivity, and stability.

Main Results:

• The CNTs@MoS2 heterostructure exhibits well-defined p-n junctions facilitating efficient charge transport.
• The sensor achieved a high response of 94% to 500 ppm NH3 at room temperature.
• Rapid response (36 s) and recovery (68 s) times were observed.
• Enhanced sensor performance under high humidity due to humidity-assisted interfacial charge transfer.
• Demonstrated long-term stability with ~80% response retention after 150 days.

Conclusions:

• The CNTs@MoS2 core-shell heterostructure is a promising material for high-performance room-temperature NH3 sensing.
• The synergistic integration of MoS2 and CNTs significantly enhances gas adsorption and charge transfer.
• Humidity-assisted charge transfer offers a strategy to improve sensor performance in humid environments.
• This work provides a design blueprint for developing advanced gas sensors.