Oral Exhalation H₂S Sensor Based on Cu₂O/ZnO Heterostructures

Area of Science:

• Materials Science
• Chemical Sensors
• Nanotechnology

Background:

• Detecting hydrogen sulfide (H2S) in exhaled breath for health assessment is challenging due to the need for portable, room-temperature sensors.
• Existing sensors often struggle with sensitivity and performance at lower temperatures.

Purpose of the Study:

• To synthesize and characterize Cu2O/ZnO heterostructures for highly sensitive H2S detection.
• To develop a portable sensor for real-time H2S monitoring in exhaled breath.
• To explore the potential of these sensors for chronic disease diagnostics.

Main Methods:

• Utilized a two-dimensional (2D) electrodeposition in situ assembly method with semisine wave voltage.
• Fabricated CuZnO nanoarrays using direct current voltage for comparison.
• Investigated gas sensing properties at room and sub-zero temperatures (-20 °C).

Main Results:

• Achieved a high response of 8.53 × 10^4 to 1 ppm H2S at room temperature with a 10 ppb detection limit.
• Demonstrated a response of 42 to 10 ppm H2S at -20 °C.
• Cu2O/ZnO sensors showed ~3774 times greater response to 50 ppm H2S compared to CuZnO sensors.

Conclusions:

• The p-n heterojunctions and sulfuration reaction in Cu2O/ZnO heterostructures are key to their superior gas-sensing performance.
• Successfully applied the Cu2O/ZnO sensor for H2S detection in human exhaled breath.
• Paved the way for advanced portable room-temperature breath sensors for disease monitoring.