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 640m2 g −1 ). Characterisation ofthe gold loaded materials with small and wide angle X-ray diffraction, N2 adsorption, scanning electron microscopy (SEM),transmissionelectronmicroscopy (TEM),thermogravimetric analysis (TGA),infrared spectroscopy (FTIR), and diffuse reflectance UV–vis spectroscopy revealed that the prepared gold containing SBA-15 materials were ordered and thatthey contained two distinct sizes of gold nanoparticles (∼40nm and ∼3–5nm). High resolution TEM images of prepared materials that had been etched using potassium hydroxide showed thatthe smaller gold nanoparticles were incorporated within the walls of the mesoporous silica.