Preparation of TiO2/Carbon Nanotubes/Reduced Graphene Oxide Composites with Enhanced Photocatalytic Activity for the Degradation of Rhodamine B

Abstract

In this report, ternary titanium dioxide (TiO2)/carbon nanotubes (CNTs)/reduced graphene oxide (rGO) composites were fabricated by a facile and environmentally friendly one-pot solvethermal method for the removal of Rhodamine B (RhB). Its structures were represented by X-ray powder diffraction (XRD), Raman spectrometry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic performance was tested by the degradation efficiency of RhB under UV-vis light irradiation. The experimental results indicated that photocatalytic activity improved as the ratio of CNTs:TiO2 ranged from 0.5% to 3% but reduced when the content increased to 5% and 10%, and the TiO2/CNTs/rGO-3% composites showed superior photocatalytic activity compared with the binary ones (i.e., TiO2/CNTs, TiO2/rGO) and pristine TiO2. The rate constant k of the pseudo first-order reaction was about 1.5 times that of TiO2. The improved photocatalytic activity can be attributed to the addition of rGO and CNTs, which reduced the recombination of photo-induced electron-hole pairs, and the fact that CNTs and rGO, with a high specific surface area and high adsorption ability to efficiently adsorb O2, H2O and organics, can increase the hydroxyl content of the photocatalyst surface.

Keywords

• titanium dioxide
• carbon nanotubes
• graphene
• photocatalyst