Unexpected refacetting of palladium nanoparticles under atmospheric N2 conditions

Abstract

We demonstrate an unexpected refacetting process of Pd nanoparticles, induced by N₂ under atmospheric pressure at elevated temperatures, by in situ TEM observations. The morphology changes, with a notable increase in the fraction of Pd{110} facets, were visualized by atomic-scale TEM images and further explained by theoretical calculations. Firm evidence and rational understanding revealed that the “inert” gas N₂ has the ability to modify the structure of metal nanoparticles. This surprising effect should be considered seriously in vast chemical applications that use N₂ as a carrier gas or protective atmosphere.