Ultra-Sensitive NO₂ Detection at Room Temperature Enabled by ZnO@MoO₃ Core-Shell Nanocomposite

Area of Science:

• Materials Science
• Environmental Science
• Nanotechnology

Background:

• Sensitive detection of nitrogen dioxide (NO2) is vital for environmental protection and public health.
• Metal oxide-based sensors are widely explored for gas detection due to their tunable properties.

Purpose of the Study:

• To develop a highly sensitive and selective room-temperature NO2 sensor.
• To investigate the synergistic effects in ZnO@MoO3 core-shell nanocomposites for gas sensing applications.

Main Methods:

• Fabrication of ZnO@MoO3 core-shell nanocomposites using a stepwise solution self-assembly and heat-treatment method.
• Characterization of the nanocomposite's structure and morphology.
• Evaluation of the sensor's performance for NO2 detection at room temperature, including response, selectivity, stability, and repeatability.

Main Results:

• The ZnO@MoO3 sensor demonstrated a high response value of 5.4 to 2 ppm NO2 at room temperature.
• The sensor exhibited excellent selectivity against common interfering gases (CO2, NH3, methanol, ethylene, trimethylamine).
• Outstanding stability and repeatability were observed under varying humidity conditions.

Conclusions:

• The ZnO@MoO3 core-shell nanocomposite offers a promising platform for advanced NO2 sensing.
• Synergistic effects between ZnO and MoO3, facilitated by heterostructures, enhance electron transfer and sensing performance.
• This work presents an effective strategy for developing next-generation metal oxide composite gas sensors.