Photocatalytic activity of hybrid gold-titania nanocomposites

This paper describes a new and straightforward approach for the synthesis of high temperature stable hybrid Au/TiO2 anocomposites (NCs). This novel approach allows one to produce Au cores decorated with titanium dioxide (TiO2) nanoparticles owing to a modified solvothermal process that makes use of gold salt HAuCI4 and Titanium(IV) butoxide as the gold and titanium precursors, and Dimethyl Sulfoxide (DMSO) as a solvent. The structure and morphology of the Au/TiO2 nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Energy Dispersive X-ray Fluorescence (EDXRF), high-resolution transmission electron microscopy (HRTEM), Raman and photoluminescence spectroscopies. Based on FTIR and TDA/TGA measurements, a proposed mechanism for the formation of Au/TiO2 NCs in DMSO (without adding of any other reagents) is discussed in this contribution. Optical absorption measurement showed that the Au/TiO2 NCs exhibit a UV significant absorption peak clearly blue-shifted with respect to that of bulk TiO2. The produced nanocomposites consist of monodisperse quasi-spherical AuNPs core decorated with TiO2 anatase phase (average size of 11 nm). The hybrid Au/TiO2 NCs exhibit a high thermal stability at higher temperature. The high crystalline quality, together with the easy synthesis process, makes the Au/TiO2 NCs a promising candidate for many applications such as optoelectronics and water photolysis for hydrogen production.