Cerium(III) Ion Sensing Based on Graphene Quantum Dots Fluorescent Turn-Off

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Graphene quantum dots (GQDs) are promising nanomaterials with unique optical properties.
• Developing selective and sensitive sensors for metal ion detection is crucial for environmental monitoring and chemical analysis.
• Photoluminescent nano-chemosensors offer advantages in sensitivity and selectivity for ion detection.

Purpose of the Study:

• To synthesize graphene quantum dots (GQDs) using a hydrothermal method.
• To utilize the synthesized GQDs as a photoluminescent nano-chemosensor for the detection of cerium ions (Ce³⁺) in aqueous solutions.
• To investigate the selectivity and sensing mechanism of GQDs towards Ce³⁺.

Main Methods:

• Synthesis of GQDs via hydrothermal method.
• Characterization of GQDs using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-Visible absorption, and fluorescence emission spectroscopy.
• Fluorescence spectroscopy was employed to study the interactions of GQDs with various cations, including Ce³⁺.

Main Results:

• GQDs with sheet diameters primarily between 15-20 nm were successfully synthesized.
• The synthesized GQDs exhibited selective fluorescence quenching in the presence of Ce³⁺ ions compared to other common cations and lanthanide ions.
• The fluorescence quenching mechanism was attributed to a redox interaction between Ce³⁺ ions and the GQDs surface.

Conclusions:

• Hydrothermally synthesized GQDs function as effective photoluminescent nano-chemosensors.
• GQDs demonstrate high selectivity for Ce³⁺ ion detection in aqueous solutions.
• The developed sensing platform offers a promising approach for the selective detection of Ce³⁺ based on fluorescence quenching.