Angle Resolved TEM Imaging of Pt Nanoparticles

Particle shape and size are two of the most important characteristics of nanoparticulate catalysts that determined their activity and selectivity. In many studies, the shapes of nanoparticles are characterized using transmission electron micrographs obtained at a single nanoparticle orientation and thus, the shape determination is based on viewing a single cross-sectional profile of the nanoparticle. A full determination of particle shape should require viewing over a range of angles. In this work Pt nanoparticles with controlled shapes and sizes have been synthesized using a high pressure technique. Angle resolved transmission electron microscopy techniques (electron tomography) are necessary to view the crystals over a range of orientations and determine their three dimensional shapes. In this work, angle resolved TEM imaging of nanoparticles reveals information about the nanoparticle shape and orientation on substrates that cannot be determined from single cross-sectional TEM images. Angle resolved TEM imaging of nanoparticles will be very valuable in catalysis and in the fields where the shapes of nanoparticles play an important role.