Functionalized Silicate Sol−Gel-Supported TiO₂−Au Core−Shell Nanomaterials and Their Photoelectrocatalytic Activity

The N-[3-(trimethoxysilyl)propyl]ethylenediamine (EDAS) derived silicate matrix supported core−shell TiO₂−Au nanoparticles (EDAS/(TiO₂−Au)_nps) were prepared by NaBH₄ reduction of HAuCl₄ precursor on preformed TiO₂ nanoparticles in the presence of EDAS monomer. The core−shell (TiO₂−Au)_nps nanoparticles were stabilized by the amine functional group of the EDAS silicate sol−gel network. The potential application of this EDAS/(TiO₂−Au)_nps modified electrode toward the photoelectrochemical oxidation of methanol was explored. The EDAS/(TiO₂−Au)_nps modified electrode showed a 12-fold enhancement in the catalytic activity toward photoelectrooxidation of methanol when compared to TiO₂ 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/(TiO₂−Au)_nps nanocomposite. A methanol oxidation peak current density of 12.3 mA cm⁻² was achieved at an optimum loading of Au_nps on TiO₂ particles. This novel amine functionalized EDAS silicate sol−gel stabilized core−shell (TiO₂−Au)_nps nanomaterial could be an excellent candidate for the photocatalytic and photoelectrochemical applications.