Microwave-assisted exfoliation and tearing of graphene oxide in the presence of TiO2 nanoparticles

In this paper, we present a facile approach to reduce, exfoliate, and tear graphene oxide (GO) sheets, which can be used to produce graphene quantum dots. The prepared GO sheets were easily exfoliated and teared under UV and microwave (MW) irradiation in the presence of TiO2 nanoparticles (NPs). Results show that the GO sheets can be reduced/fragments by MW depending on the irradiation power. We found that; GO sheets are partially reduced under MW irradiation with a power of 90 W and crushed to nanosheets by increasing the MW power up to 450 W. In addition, the photoluminescence peak is broadened, confirming a decrease in the size of GO sheets. The optical bandgap of the nanosheets was measured about 3 eV in agreement with the results of the tight-binding calculation. In addition, HR-TEM results show the size of prepared nanosheets is about 20 nm, while X-ray photoelectron spectroscopy shows a bond formation between residual TiO2 NPs and the prepared nanosheets.