Image courtesy of Chem. Comm.

Abstract

Shape stability of Pd–Rh core–frame nanocubes was studied by in situ heating transmission electron microscopy. Pd–Rh nanocubes could maintain cubic shape at elevated temperature compared with pure Pd. The surface diffusion process of Rh onto {100} side surfaces is believed to postpone the degradation to higher temperature.

Impact Statement

Applications using nanoparticles, especially catalysis, are highly dependent on the surface properties. The authors used the Fusion heating capabilities to understanding surface changes of Pd nanocubes as a function of temperature. They discovered
that significant changes occurred at temperatures lower than typical operating temperatures for catalyst activity. These changes included rounded corners and sintering with neighboring nanocubes. To increase the thermal stability the researchers
coated the Pd nanocubes with an Rh frame, creating a Pd-Rh core-frame nanocube. They found that the Rh increased the thermal stability by up to 100° C. While pure Pd nanocubes formed rounded edges at 400° C after only 8.5 min, Pd-Rh nanocubes
continued to have sharp corners after 1 hr. at 500° C. High resolution TEM and STEM images and EDS spectrum images were taken on a JEOL ARM200F.