To study their thermal stability, we observed Pt colloidal nanoparticles on terraced graphene layers at high temperatures using aberration-corrected transmission electron microscopy. Not only Pt nanoparticles but also single Pt atoms were formed on the graphene layers by heating Pt colloids to 500-800°C. High resolution in situ observation showed that Pt nanoparticles and single atoms anchored to the edge of the graphene layers were relatively stationary under elevated temperatures, although some Pt atoms migrated on the graphene surfaces. The results indicated that the Pt single atoms at the edge of the graphene exhibited high-temperature stability.
Imaged the behavior of Pd nanoparticles on the surface of exfoliated multilayer graphene. Used aberration corrected TEM and STEM to visualize the evolution of Pd nanoparticle and single Pd atoms on the surface. Found that Pd nanoparticles and atoms were more stable when anchored to the edges of graphene.