Embedding colloidal nanoparticles inside mesoporous silica using gas expanded liquids for high loading recyclable catalysts

The ability to tune the structural and chemical properties of colloidal nanoparticles (NPs) makes them highly advantageous for studying activity and selectivity dependent catalytic behaviour. Incorporating pre-synthesised colloidal NPs into porous support materials remains a challenge due to poor pore wetting and permeability. In this report, monodisperse, composition-controlled AgPd alloy NPs were synthesised and embedded into mesoporous silica SBA-15 using carbon dioxide and expanded hexane. Impregnation resulted in high metal loading without the requirement for surface pre-treatments. The catalytic activity, reaction profiles and recyclability of the alloy NPs embedded in SBA-15 and immobilised on non-porous SiO2 are evaluated. The NPs incorporated within the SBA-15 porous network showed significantly greater recyclability performance compared to non-porous SiO2.