Aqueous-Phase Synthesis of Ag–TiO₂–Reduced Graphene Oxide and Pt–TiO₂–Reduced Graphene Oxide Hybrid Nanostructures and Their Catalytic Properties

We demonstrate an aqueous solution method for the synthesis of a Ag–TiO₂–reduced graphene oxide (rGO) hybrid nanostructure (NS) in which the Ag and TiO₂ particles are well dispersed on the rGO sheet. The Ag–TiO₂–rGO NS was then used as a template to synthesize Pt–TiO₂–rGO NS. The resulting hybrid NSs were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, UV–vis spectroscopy, Raman spectroscopy, inductively coupled plasma mass spectrometry (ICP-MS), and catalytic studies. It was found that TiO₂–rGO, Ag–TiO₂–rGO and Pt–TiO₂–rGO NSs all show catalytic activity for the reduction of p-nitrophenol to p-aminophenol by NaBH₄, and that Pt–TiO₂–rGO NS exhibits the highest catalytic activity as well as excellent stability and easy recyclability.