Graphene Quantum Dot - Titania Nanoparticle Composite for Photocatalytic Water Splitting

Graphene quantum dots (GQDs) of different sizes Were synthesized by the top-down approach, using charcoal as the precursor material. Size and absorption characteristics of synthesized GQDs were analyzed using Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AIM), Photoluminescence Spectroscopy (PE), and UV-vis Spectroscopy. The results showed that GQDs with an average height of 8.5 nm, synthesized at a relatively lower temperature of 85 degrees C,exhibited higher UV and visible light absorption. GQD concentration was varied to form 0.5, 1,2.5 and 5 wt.% GQD-titania (TiO2) nano composites. Surface morphology of the composite was examined using Scanning Electron Microscopy (SEM). Photocatalytic activity of the samples was assessed from methylene blue dye degradation in UV irradiation at 340nm. A distinguishable trend for pure TiO2 and composites at various concentrations were observed.