Engineering an Ultrafast Ambient NO₂ Gas Sensor Using Cotton-Modified LaFeO₃/MXene Composites

Area of Science:

• Materials Science
• Chemical Sensing
• Nanotechnology

Background:

• Developing efficient room-temperature gas sensors is crucial for environmental monitoring and safety.
• Nitrogen dioxide (NO2) is a harmful pollutant requiring sensitive detection methods.

Purpose of the Study:

• To create a room-temperature NO2 gas sensor with enhanced performance using cotton-modified LaFeO3 (CLFO) and MXene.
• To investigate the sensing mechanisms and practical applicability of the fabricated sensor.

Main Methods:

• Hydrothermal synthesis of LaFeO3 (LFO), CLFO, and CLFO/MXene composites.
• Fabrication and characterization of the gas sensor.
• In situ FTIR, GC-MS, and near-ambient pressure XPS for interaction analysis.
• Finite-difference time-domain simulations for nanoscale interaction modeling.

Main Results:

• The MXene/CLFO sensor exhibited p-type behavior and fully recoverable sensing for NO2 at room temperature.
• Achieved a high response of 14.2 times at 5 ppm NO2, with a response time of 2.7 s and recovery time of 6.2 s.
• Demonstrated excellent stability and sensitivity attributed to surface interactions and charge transfer.

Conclusions:

• The CLFO/MXene composite is a promising material for high-performance room-temperature NO2 gas sensing.
• The developed sensor shows potential for practical applications, including a prototype IoT-based detection system.
• This research provides insights into low-detection-limit gas sensing technologies.