Ultrasensitive Room-Temperature NO₂ Gas Sensor Based on MXene-Cu₂O Composites

Area of Science:

• Materials Science
• Chemical Sensing
• Nanotechnology

Background:

• Real-time trace-level nitrogen dioxide (NO2) quantification at room temperature is crucial for occupational safety and public health.
• Existing sensors often require elevated temperatures, limiting their practical application.
• Metal-oxide semiconductor (MOS) based sensors are promising but require performance optimization.

Purpose of the Study:

• To develop a highly sensitive and selective room-temperature NO2 sensor.
• To investigate the effect of MXene incorporation on Cu2O sensing properties.
• To elucidate the mechanisms behind the enhanced gas sensing performance.

Main Methods:

• Hydrothermal synthesis of MXene-Cu2O composites.
• Systematic evaluation of varying MXene content (0.84 wt % identified as optimal).
• Characterization of sensor performance including sensitivity, response/recovery time, detection limit, selectivity, and stability.

Main Results:

• The 0.84 wt % MXene-Cu2O composite demonstrated a 4-fold increase in sensitivity compared to pure Cu2O.
• Achieved a short response time of 55 s and recovery time of 35 s.
• Exhibited a low detection limit of 10 ppb, high selectivity, good reversibility, and long-term stability.

Conclusions:

• MXene-Cu2O composites offer a promising platform for room-temperature NO2 sensing.
• Engineered interfacial architectures and oxygen vacancy engineering are key to enhanced sensing performance.
• This approach provides a novel strategy for developing sensitive MOS-based gas sensors.