Recent Progress on Functionalized Graphene Quantum Dots and Their Nanocomposites for Enhanced Gas Sensing...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Graphene quantum dots (GQDs) and their nanocomposites represent a significant advancement in gas-sensing technology.
• Functionalized GQDs offer tunable properties for enhanced gas detection capabilities.

Purpose of the Study:

• To provide a comprehensive review of the recent progress in the construction methods and applications of functionalized GQDs and GQD-based nanocomposites for gas sensing.
• To elucidate the underlying gas-sensing mechanisms, including Fermi-level control and charge carrier depletion theory.

Main Methods:

• Reviewing literature on the synthesis and functionalization of GQDs.
• Analyzing the integration of GQDs with various matrices (polymers, metal oxides, 2D materials) to form nanocomposites.
• Examining gas-sensing performance metrics like sensitivity, selectivity, stability, response/recovery times, and limit of detection (LOD).

Main Results:

• Functionalized GQDs and their nanocomposites demonstrate significant enhancements in gas-sensing performance.
• GQD-based sensors exhibit excellent sensitivity and selectivity towards various hazardous gases.
• Reported LODs for toxic gases are typically in the 1-10 ppm range, with some achieving ultra-low ppb levels (e.g., 0.01 ppb for formaldehyde).

Conclusions:

• Functionalized GQDs and their nanocomposites are pivotal in developing advanced gas sensors.
• The unique properties of GQDs enable highly sensitive and selective detection of hazardous gases.
• Continued research in GQD-based materials promises further breakthroughs in environmental monitoring and safety applications.