Photocatalytic Degradation of Methylene Blue from Aqueous Solutions by rGO/TiO2 Nanocomposites

Methylene blue (MB), as a typical pollutant in industrial dyestuff wastewater, has caused serious water pollution. Therefore, reduced graphene oxide (rGO)/TiO 2 nanocomposites were synthetized by a simple hydrothermal technique and used as photocatalyst to degrade MB. It was illustrated when TiO 2 nanoparticles were loaded 5wt.% rGO framework, nanocomposite had a huge specific surface area of 176.45 m 2 g −1 and the average pore size of 4.25 nm. Effects of the rGO fraction in rGO/TiO 2 photocatalyst, the rGO/TiO 2 photocatalyst content, the initial pH, and the initial MB concentration on MB degradation efficiency were studied. The degradation efficiency about 98.18% was acquired at 5rGO/TiO 2 content of 0.4 g L −1 , pH = 6, MB concentration of 60 mg L −1 . The degradation efficiency of 5rGO/TiO 2 for MB was still as high as 86.24% after the tenth cycles, demonstrating rGO/TiO 2 nanocomposites were useful for the practical application. The potential photocatalytic mechanism of rGO/TiO 2 for MB degradation was immediate oxidative degradation procedure, and the combined action of O 2 ∙ - , OH ∙ and h + can contribute to the photocatalytic degradation of MB. Furthermore, the photocatalytic degradation kinetic of rGO/TiO 2 for MB under UV irradiation was first-order model.