Thanks to a groundbreaking new method, scientists have created the first 3D super-resolution maps of catalytic activity on an individual catalytic nanoparticle while reactions are occurring. Catalysts are used in manufacturing everything from stain remover to rocket fuel; they make production more efficient by facilitating chemical reactions. Each catalyst being studied is only about 200 nanometers in diameter (it would take a chain of approximately 500 nanocatalysts to equal the thickness of a single sheet of paper). Even at the nanoscale, reactions can vary greatly in distribution and intensity on the surface. To precisely map each location in situ, researchers first initiate a reaction that creates fluorescent product molecules. When excited by a laser, these molecules flash. The flashes are recorded using a camera capable of detecting single particles of light and mapped much like using pushpins to mark locations on a map. Taking advantage of the uniform, spherical shape of the nanocatalysts, the researchers then apply geometry to transpose the dots from a flat map onto a 3D globe. The fluorescence intensity further indicates in which hemisphere a reaction happened, as those nearer the light source have a stronger signal. Mapping reactions in super-resolution 3D is vital to understand what is going on at specific sites on the surface of the catalyst and fine tune particle distributions to create better catalysts.
Geometry-Assisted Three-Dimensional Superlocalization Imaging of Single-Molecule Catalysis on Modular Multilayer Nanocatalysts