Indium Tin-Oxide Wrapped 3D rGO and TiO2 Composites: Development, Characterization, and Enhancing Photocatalytic Activity for Methylene Blue

Abstract

A hybrid material of indium tin-oxide (ITO) wrapped titanium dioxide and reduced graphene oxide (ITO-rGO and TiO2) was prepared using a facile hydrothermal technique. TiO2 nanorods were in situ grown on the surface of rGO (rGO and TiO2), and which was then assembled onto ITO substrate layer by layer with formation of a 3D structure. ITO-rGO and TiO2 exhibit low charge transfer resistance at the electrode-electrolyte interface and have good photoresponsive ability. Methylene blue (MB) can be effectively adsorbed and enriched onto ITO-rGO and TiO2 surface. The adsorption kinetics and thermodynamics of ITO-rGO and TiO2 were evaluated, showing that the exothermic and entropy-driven reaction were the main thermodynamic processes, and the Langmuir isotherm was the ideal model for adsorption fitting. Meanwhile, ITO greatly improved degradation of rGO and TiO2 because electrons can be collected by ITO before recombination and MB can easily enter into the 3D structure of rGO and TiO2. The highest photodegradation rate of MB reached 93.40% for ITO-rGO and TiO2 at pH 9. Additionally, ITO-rGO and TiO2 successfully solved the problems of being difficult to recycle and causing secondary pollution of traditional TiO2 catalysts. Therefore, ITO-rGO and TiO2 may be a potential photocatalyst for degrading organic pollutants in water.