Synthesis of Chiral Nematic Mesoporous Metal and Metal Oxide Nanocomposites and their Use as Heterogeneous Catalysts

We report the synthesis of chiral nematic mesoporous metal and metal oxide nanocomposites containing zinc or copper prepared through a vacuum-assisted loading of the metal precursor into a chiral nematic mesoporous silica template followed by high-temperature treatment. Significant metal loading into the template was achieved after a single loading cycle (up to 55 % of the pore volume) as confirmed by nitrogen sorption measurements. Growth of the metal nanoparticles was contained within the porous silica template, and subsequent removal of the template afforded free-standing chiral nematic metal oxide films with surface areas up to 200 m(2)/g. To demonstrate the utility of these high surface area materials, we used the prepared CuO material as a heterogeneous catalyst for click reactions. Our prepared CuO showed excellent activity (95 % conversion after seven hours) when compared to commercially available CuO nanoparticles (20 % conversion after 24 hours) owing to its considerably higher surface area. Moreover, the prepared CuO material maintained high activity (>70 % conversion) after four cycles.