Te@Se Core-Shell Heterostructures with Tunable Shell Thickness for Ultra-Stable NO₂ Detection.

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Effective long-term monitoring of trace nitrogen dioxide (NO2) is crucial for ecological and public health.
• Two-dimensional (2D) Tellurium (Te) shows potential for NO2 detection due to its electronic properties but suffers from poor stability.
• Instability limits the practical application of Te as a gas-sensing material in various conditions.

Purpose of the Study:

• To engineer stable and highly sensitive 2D gas-sensing materials for NO2 detection.
• To overcome the stability limitations of pure 2D Tellurium.
• To explore the potential of core-shell heterostructures for enhanced gas sensing performance.

Main Methods:

• Synthesis of 2D single-elemental Te@Se heterostructures using a solvothermal method.
• Characterization of the core-shell structure and its properties.
• Evaluation of NO2 sensing performance, including response, recovery times, and long-term stability.

Main Results:

• The Te@Se heterostructures exhibited an exceptionally high response (622%) to 1 ppm NO2 at room temperature.
• Achieved ultrafast response (10 s) and recovery (30 s) times for NO2 detection.
• Demonstrated excellent stability in sensing performance over 90 days, attributed to the ultrathin Se shell (4-6 nm).

Conclusions:

• 2D Te@Se core-shell heterostructures offer a viable strategy for high-performance NO2 gas sensing.
• The Se shell effectively enhances the stability and performance of Te-based gas sensors.
• These findings open new avenues for developing advanced single-element core-shell heterojunctions for gas detection applications.