Metal free, sunlight and white light based photocatalysis using carbon quantum dots from Citrus grandis: A green way to remove pollution

In this work, we have developed a facile and green synthesis of Undoped carbon quantum dots (UCQDs) and N-doped carbon quantum dots (NCQDs) from naturally available Pomelo (Citrus maxima or Citrus grandis) juice as a precursor using one-step hydrothermal method. As synthesized CQDs were characterized by X Ray Diffraction (XRD), UV-Visible spectroscopy, Photoluminescence (PL), Raman Spectroscopy, Fourier transform infrared spectroscopic (FTIR) technique and Transmission electron microscopy (TEM) techniques. Moreover, we have demonstrated that both the prepared CQDs could serve as an excellent photocatalyst towards the degradation of the Methylene Blue (MB) dye under direct sun light radiation. The degradation mechanism of MB dye could be approximated as pseudo - first order kinetics according to the Langmuir - Hinshelwood model.