Synthesis of carbon dots from carrot, orange, and cucumber peels by green hydrothermal method and their antioxidant properties

Abstract Carbon dots (CDs) have emerged as promising nanomaterials due to their unique optical properties, biocompatibility, and potential applications. In this study, CDs were successfully synthesized from carrot, orange, and cucumber peels using a hydrothermal‐assisted green method. Various analyses, including XRD, EDAX, FTIR, and FESEM, were conducted to investigate their structural characteristics, elemental composition, surface functional groups, and morphology. UV–visible and PL spectroscopy were used to examine their optical properties. XRD confirmed the CDs' structural formation, while EDAX revealed carbon weight percentages of 52%, 59%, and 58% for carrot, orange, and cucumber peels, respectively. FTIR analysis identified epoxy and hydroxyl functional groups containing carbon, hydrogen, and oxygen atoms. FESEM images showed a spherical morphology. Under UV light, the synthesized CDs exhibited green fluorescence. Fluorescence studies demonstrated maximum emissions at excitation wavelengths of 360 nm, 350 nm, and 340 nm for carrot, orange, and cucumber‐derived CDs, respectively. As an application, the antioxidant activity of CDs was measured. The results indicated that CDs derived from orange peel exhibited the highest antioxidant efficiency, reaching 87%. The results revealed that the CDs exhibit strong fluorescence and antioxidant properties, with orange peel‐derived CDs showing the highest antioxidant activity (87%). Using fruit peels as precursors provides a sustainable approach to waste management and offers a cost‐effective method for producing CDs with potential applications in bioimaging, sensing, and catalysis.