Ultra-sensitive IDE-based ammonia sensor fabricated using green synthesized graphene nanoplatelets and a TiO₂ based...

Area of Science:

• Materials Science
• Environmental Science
• Nanotechnology

Background:

• Reliable, sensitive, and economical gas sensors are essential for environmental monitoring.
• Ammonia (NH3) detection is critical for various environmental and industrial applications.
• Existing sensors often require elevated temperatures or lack sufficient sensitivity and speed.

Purpose of the Study:

• To develop a room-temperature ammonia (NH3) gas sensor using graphene nanoplatelet (GnP) and GnP-TiO2 composite.
• To evaluate the performance of the developed sensor in terms of sensitivity, response, and recovery times.
• To demonstrate the applicability of the GnP-TiO2 composite for low-concentration NH3 detection.

Main Methods:

• Green synthesis of graphene nanoplatelets (GnPs) using tea extract and a kitchen mixer.
• Hydrothermal synthesis of titanium dioxide (TiO2) and GnP-TiO2 composite.
• Fabrication of an interdigitated electrode (IDE) based chemiresistive sensor.

Main Results:

• The GnP-TiO2 composite sensor demonstrated an eight-fold higher response than the GnP sensor at 100 ppm NH3.
• At 100 ppb NH3, the GnP-TiO2 composite exhibited significantly faster response (15 s) and recovery (30 s) times.
• The composite sensor showed a ~17-fold faster response and ~3.5-fold quicker recovery compared to the GnP sensor at low concentrations.

Conclusions:

• The developed GnP-TiO2 composite is highly effective for ammonia (NH3) sensing at room temperature.
• The composite material offers superior sensitivity and rapid response/recovery characteristics, especially at ppb levels.
• This study highlights the potential of eco-friendly GnP-TiO2 composites for practical environmental monitoring applications.