Light-controlled nanoparticle catalysts
Nanoparticle science has advanced rapidly over the last decade, with self-assembly being the most efficient way of creating larger structures from nanoparticles. Recent work has also shown that light can be used to signal assembly or disassembly of nanoparticles.The EU-funded 'Photoinduced catalysis in a nanoparticle system' (PHOTOCAT) project aimed to create a nanoparticle system that assembles into a catalytic matrix when exposed to light. The project developed two different self-assembling nanoparticle systems: a so-called 'nanobowl' structure, and a 3D nanoparticle matrix.A bowl-shaped metallic nanoparticle aggregate, the nanobowl can be adjusted to hold various nano-scale objects and chemicals. Researchers attached photo-responsive molecules to the interior surface of the nanobowl, which bind specific molecules or enzymes when exposed to light. The second system is made up of metallic nanoparticles with light-activated 'switches'. When exposed to ultraviolet light, these nanoparticles aggregate to form a regular crystalline matrix structure with spaces called nanopores. PHOTOCAT showed that these pores function as reaction chambers, where the reaction between small molecules in the solution is significantly sped up. The system could also be disassembled and reassembled repeatedly. These systems offer huge potential for precise control of chemical reactions using light waves. PHOTOCAT has thus advanced the state of the art in nanoparticle chemistry.
