Green Synthesis of Self-Passivated Fluorescent Carbon Dots Derived from Rice Bran for Degradation of Methylene Blue and Fluorescent Ink Applications

Recently, natural products are the powerful carbon source to synthesize carbon dots (CDs) with interesting physical and chemical properties. In this present work, we report a facile hydrothermal synthesis method for preparing fluorescent carbon dots using a biogenic precursor of rice bran without any surface passivation agent. The synthetic methodology was easy, simple, environmental friendly and convenient. Structural and optical properties of the RB-CDs have been studied by UV-visible, Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Fluorescence spectra and X-ray photoelectron spectroscopy (XPS) techniques. The prepared RB-CDs exhibited green emission upon irradiation with UV light and the calculated fluorescence quantum yield (QY) was found to be 7.4%. The morphological features of the synthesized RB-CDs were characterized by High-Resolution Transmission Electron Microscopy (HR-TEM), the average size of the RB-CDs was found to be 2.96 nm. The synthesized RB-CDs were beneficially applied as a catalyst for the catalytic degradation of methylene blue (MB) dye using NaBH4 as the reducing agent in the ambient conditions. The degradation of MB dye under light illumination was 89.20% in 30 min. Further, the obtained highly fluorescent RB-CDs were efficiently utilized as a fluorescent ink for luminescent pattern printing (patterning agent) in the anti-counterfeiting applications.

Automated summary

Natural products have been utilized as a powerful carbon source to synthesize carbon dots with interesting physical and chemical properties. A facile hydrothermal synthesis method using rice bran as a biogenic precursor was reported for preparing fluorescent carbon dots without any surface passivation agent. The synthesized RB-CDs exhibited green emission with a fluorescence quantum yield of 7.4% and were efficiently applied as a catalyst for the degradation of methylene blue dye, as well as a fluorescent ink for anti-counterfeiting applications.