Natural Source-Based Graphene as Sensitising Agents for Air Quality Monitoring

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Carbon-based nanomaterials are crucial for developing advanced sensors.
• Nitrogen doping enhances the electronic and chemical properties of carbon materials.
• Developing cost-effective and sensitive gas sensors is essential for environmental monitoring.

Purpose of the Study:

• To synthesize nitrogen-doped carbon nanoparticles (N-CNPs) and nitrogen-doped graphene quantum dots coupled to nanosheets (N-GQDs-NSs) from natural carbon powder.
• To characterize the synthesized materials using various spectroscopic and microscopic techniques.
• To evaluate the performance of these materials as sensitizing agents in an optical fiber-based gas sensor for volatile organic compounds (VOCs).

Main Methods:

• Chemical oxidation and centrifugation separation were employed for material synthesis.
• Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), High-Resolution Transmission Electron Microscopy (HR-TEM), Atomic Force Microscopy (AFM), UV-Visible (UV-Vis), and Fluorescence (FL) spectroscopy were used for characterization.
• An optical fiber-based sensing configuration was utilized to detect VOCs.

Main Results:

• Successfully synthesized N-CNPs and N-GQDs-NSs with nitrogen doping.
• Characterization confirmed the formation of nitrogen-doped carbon materials with an average plane dimension of 50 nm and a smooth surface.
• The sensor demonstrated a fast response (tens of seconds) and excellent repeatability for methanol vapor detection.
• Low limits of detection were achieved: 4.3 ppm for methanol, 4.9 ppm for ethanol, and 10.5 ppm for propanol under atmospheric conditions.

Conclusions:

• The study presents an efficient method for preparing N-CNPs and N-GQDs-NSs as effective sensitizing agents.
• The developed optical fiber gas sensor exhibits high sensitivity, fast response, and good repeatability for VOC detection.
• These findings highlight the potential of these nitrogen-doped carbon materials for diverse sensing applications, including remote chemical vapor detection and air quality monitoring.