Photoactivity of reducing graphene oxide and titanium dioxide composite for cinnamic acid degradation

Abstract

Reducing graphene dioxide (rGO) and titanium dioxide (TiO2) composites with various rGO/TiO2 ratios were prepared by hydrothermal method, in which rGO was synthesized from graphene powder according to modified Hummers method using microwave. Physico-chemical characteristics of the samples were investigated by the methods of N2 adsorption-desorption measurements, X-ray diffraction, Raman, Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). rGO-TiO2 (1:25) catalyst had smaller particle size and higher surface area than whose of pure TiO2. Moreover, this modification also extended the region of photon absorption of TiO2 towards the visible range of 397437 nm. The catalytic activity was investigated by photodegradation of cinnamic acid (CA) solution, which have been shown higher activity than that of the pure TiO2 catalyst. The optimum conditions in this study for the degradation of CA were determined as follows: the ratio rGO/TiO2 of 1:25, catalyst concentration of 0.75 g·L11, oxygen supply of 0.5 L·min11, initial pH solution of 3.8 and reaction temperature of 25°C. In this condition, cinnamic acid conversion in the solution reached approximately 90% after 60 minute reaction.