Functionalized Silicate Sol−Gel-Supported TiO<sub>2</sub>−Au Core−Shell Nanomaterials and Their Photoelectrocatalytic Activity

The <i>N</i>-[3-(trimethoxysilyl)propyl]ethylenediamine (EDAS) derived silicate matrix supported core−shell TiO<sub>2</sub>−Au nanoparticles (EDAS/(TiO<sub>2</sub>−Au)<sub>nps</sub>) were prepared by NaBH<sub>4</sub> reduction of HAuCl<sub>4</sub> precursor on preformed TiO<sub>2</sub> nanoparticles in the presence of EDAS monomer. The core−shell (TiO<sub>2</sub>−Au)<sub>nps</sub> nanoparticles were stabilized by the amine functional group of the EDAS silicate sol−gel network. The potential application of this EDAS/(TiO<sub>2</sub>−Au)<sub>nps</sub> modified electrode toward the photoelectrochemical oxidation of methanol was explored. The EDAS/(TiO<sub>2</sub>−Au)<sub>nps</sub> modified electrode showed a 12-fold enhancement in the catalytic activity toward photoelectrooxidation of methanol when compared to TiO<sub>2</sub> dispersed in EDAS silicate sol−gel matrix. This improved photoelectrochemical performance is explained on the basis of beneficial promotion of interfacial charge transfer processes of the EDAS/(TiO<sub>2</sub>−Au)<sub>nps</sub> nanocomposite. A methanol oxidation peak current density of 12.3 mA cm<sup>−2</sup> was achieved at an optimum loading of Au<sub>nps</sub> on TiO<sub>2</sub> particles. This novel amine functionalized EDAS silicate sol−gel stabilized core−shell (TiO<sub>2</sub>−Au)<sub>nps</sub> nanomaterial could be an excellent candidate for the photocatalytic and photoelectrochemical applications.