Role of laser fluence in decoration of graphene nanosheets with TiO2 nanoparticles by pulsed laser ablation method

Abstract

A simple and green method to decorate graphene nanosheets is introduced, according to laser ablation of graphite target in TiO2 nanoparticle suspension. TiO2 nanoparticles were synthesized by laser ablation of a high purity titanium target in distilled water with the fundamental wavelength of pulsed Nd:YAG laser at 7 ns pulse width. 4 samples of graphene/TiO2 nanocomposites were produced by laser ablation of graphite target in TiO2 nanoparticle suspension with different laser fluence. The TiO2 nanoparticles and graphene/TiO2 nanocomposites were characterized by X-ray diffraction, field emission scanning electron microscope, transmission electron microscope, UV–Vis–NIR absorption spectroscopy, FTIR and Raman spectroscope. Micro images of nanocomposite confirm that TiO2 nanoparticles have placed and fixed on graphene nanosheets during their exfoliation from graphite target in TiO2 nanoparticles suspension. It was found that absorption intensity of graphene/TiO2 nanocomposite is higher than the pure TiO2 nanoparticles which can be beneficial to the photogeneration of electron–hole pair charge carriers for improving the photocatalytic performance. The change in the intensity ratios of Raman peaks of graphene nanosheets show that charge transfer between them and TiO2 nanoparticles has taken place. Results show that the number and size of the TiO2 nanoparticles on the graphene nanosheets can be easily tuned by laser fluence.