Hydrothermal synthesis of titanium dioxide/graphene aerogel for photodegradation of methylene blue in aqueous solution

Abstract

Titanium dioxide/graphene aerogel (TiO2/GA) was synthesized via a one-pot hydrothermal method and characterized by various spectroscopic techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscopy, Raman spectroscopy, and UV-Vis spectroscopy. The influences of pH and TiO2/GA dose on the photocatalytic performance were investigated against positive dye methylene blue (MB) under UV light control. The characterization of TiO2/GA revealed that the synthesized TiO2 nanosize of 12–22.5 nm was uniformly distributed onto the graphene layers. The bandgap of the as-prepared nanocomposite was 2.63 eV, lower than that of pure TiO2 (3.2 eV). The kinetic studies exhibited that the adsorption–desorption equilibrium was achieved after 60 min following the pseudo-second-order. Meanwhile, 99.9% of MB was eliminated after 120 min at pH 9 with a 20 mg catalyst. The degradation data were well fitted to the pseudo-first-order kinetic model. Accordingly, applying TiO2/GA as an efficient photocatalyst indicates a potential pathway for the degradation of organic contaminants in wastewater treatment.

Keywords

• TiO2
• Graphene aerogel
• Nanocomposite
• Photocatalyst
• Methylene blue