One-step green synthesis of biomass-derived graphene quantum dots as a highly selective optical sensing probe

Graphene quantum dots (GQDs) have gained a significant amount of research interest due to their good biocompatibility, low toxicity, incredible fluorescence, and intriguing physicochemical characteristics. However, the fundamental issues, such as acidic contamination and expensive product price, are still obstacles to their commercialization. In this study, we present an eco-friendly one-step approach to produce GQDs using biomass waste green precursor and relatively green solvent ‘ethanol’. This approach simultaneously addresses the issues of contaminants from strong acids and the high cost initiated by costly precursors. The results reveal that GQDs demonstrate a size range of 0.5–4 nm and a thickness of 1–3 layers of graphene. As-prepared GQDs exhibit considerable surface grafting and exceptional optical properties with a high quantum yield of 21%. These GQDs are used as a fluorescence probe to detect ferric ions (Fe3+) owing to their exclusive optical properties. A precise and selective sensor is developed with a detection limit down to 0.5 μM. This work identifies the importance of using a relatively green process and an inexpensive biomass precursor to produce high-quality GQDs that hold a promising future for use in photocatalytic, bioimaging, and practical sensing applications.