Single-step solvothermal synthesis of mesoporous Ag–TiO2–reduced graphene oxide ternary composites with enhanced photocatalytic activity

Abstract

With growing interest in the photocatalytic performance of TiO₂–graphene composite systems, the ternary phase of TiO₂, graphene, and Ag is expected to exhibit improved photocatalytic characteristics because of the improved recombination rate of photogenerated charge carriers and potential contribution of the generation of localized surface plasmon resonance at Ag sites on a surface of the TiO₂–graphene binary matrix. In this work, Ag–TiO₂–reduced graphene oxide ternary nanocomposites were successfully synthesized by a simple solvothermal process. In a single-step synthetic procedure, the reduction of AgNO₃ and graphene oxide and the hydrolysis of titanium tetraisopropoxide were spontaneously performed in a mixed solvent system of ethylene glycol, N,N-dimethylformamide and a stoichiometric amount of water without resorting to the use of typical reducing agents. The nanocomposites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, along with different microscopic and spectroscopic techniques, enabling us to confirm the successful reduction of AgNO₃ and graphite oxide to metallic Ag and reduced graphene oxide, respectively. Due to the highly facilitated electron transport of well distributed Ag nanoparticles, the synthesized ternary nanocomposite showed enhanced photocatalytic activity for degradation of rhodamine B dye under visible light irradiation.