Synthesis of very high surface area Au-SBA-15 materials by confinement of gold nanoparticles formation within silica pore walls

Very high surface area Au-SBA-15 type materials containing gold nanostructures were synthesised by oxidatively polymerizing aniline using chloroauric acid concurrently with condensing silicate in the presence of a triblock copolymer. The aforementioned synthesis resulted in significant changes to the morphology, texture, density and surface properties of the gold loaded materials as compared to SBA-15 prepared using a very similar method. The surface area of all of the prepared gold loaded materials was significantly higher than the parent SBA-15, with one material having an extremely high surface area that was more than double the parent SBA-15 (1424 m2 g−1 vs 640 m2 g−1). Characterisation of the gold loaded materials with small and wide angle X-ray diffraction, N2 adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermo gravimetric analysis (TGA), infrared spectroscopy (FTIR), and diffuse reflectance UV–vis spectroscopy revealed that the prepared gold containing SBA-15 materials were ordered and that they contained two distinct sizes of gold nanoparticles (∼40 nm and ∼3–5 nm). High resolution TEM images of prepared materials that had been etched using potassium hydroxide showed that the smaller gold nanoparticles were incorporated within the walls of the mesoporous silica.