Efficient green light-based photocatalytic removal of bilirubin by a biocompatible nanocomposite of nitrogen doped graphene quantum dots/Au

Abstract

Nitrogen-doped graphene quantum dots/Au (NGQDs/Au) nanocomposite was synthesized by hydrothermal method followed by a photochemical route. The gram-scale nitrogen-doped graphene quantum dot was synthesized by using hydrothermal method from urea and citric acid as a precursor. By adding HAuCl4 to the prepared sample, the nitrogen-doped graphene quantum dots/Au nanocomposite was made in a straightforward photochemical process. The synthesized composite was utilized directly as a biocompatible photocatalyst for bilirubin degradation under green light irradiation.The nanocomposite was characterized using FESEM, Raman, XRD, TEM, UV–Vis spectroscopy, and PL. The quantum yield of the nanocomposite was calculated. The role of surface plasmon resonance (SPR) of Au nanoparticles in reduction of the quantum yield and quantum yield effect on the photodegradation process was investigated. The photocatalytic degradation efficiency of bilirubin in presence of the synthesized nanocomposite was measured to be nearly 74.7 % after 100 min green light irradiation, which is 5 times more than blue light used in clinical phototherapy without any photocatalyst. The optical analysis results reveal that the doping of nitrogen in GQDs and compositing with gold could accelerate the suppression of charge carrier's recombination. The future application of biocompatible photocatalysts in jaundice treatment under the green light irradiation was also approved in this research.