Nitrogen-Doped Graphene Quantum Dots with Oxygen-Rich Functional Groups

TLDR

Graphene quantum dots are a novel class of quantum dots with unique properties, and doping them with heteroatoms allows tuning of these properties for advanced device applications. The authors aim to produce nitrogen‑doped GQDs with oxygen‑rich functional groups using a simple electrochemical approach. They synthesize these N‑GQDs via a straightforward electrochemical method that yields luminescent and electrocatalytically active particles. The resulting N‑GQDs, with an N/C ratio of ~4.3%, emit blue luminescence and exhibit electrocatalytic activity comparable to commercial Pt/C for the oxygen reduction reaction in alkaline media, making them suitable as metal‑free ORR catalysts and for biomedical imaging and optoelectronic applications.

Abstract

Graphene quantum dots (GQDs) represent a new class of quantum dots with unique properties. Doping GQDs with heteroatoms provides an attractive means of effectively tuning their intrinsic properties and exploiting new phenomena for advanced device applications. Herein we report a simple electrochemical approach to luminescent and electrocatalytically active nitrogen-doped GQDs (N-GQDs) with oxygen-rich functional groups. Unlike their N-free counterparts, the newly produced N-GQDs with a N/C atomic ratio of ca. 4.3% emit blue luminescence and possess an electrocatalytic activity comparable to that of a commercially available Pt/C catalyst for the oxygen reduction reaction (ORR) in an alkaline medium. In addition to their use as metal-free ORR catalysts in fuel cells, the superior luminescence characteristic of N-GQDs allows them to be used for biomedical imaging and other optoelectronic applications.