Understanding the role of ‘path’ for sacrificial substance migration during the fabrication of hollow nanostructures in PtPdCu system

PtPdCu nanoparticles (NPs) were etched by acid to prepare hollow nanostructures (HNSs). A hypothesis ‘path’ was given. The rate of Cu migration is different in amorphous and in crystalline structures, and is usually faster in amorphous structures. The fast mass transport part looked like a road for Cu migration, and it was named the ‘path’. With time passing, phase transfer occurs; the ‘path’ may shrink until it is closed. These changes of the status of the ‘path’ would affect the results of the Kirkendall effect, separate voids or big holes inside particles. This could indicate that only a 10 K temperature difference in the synthesis results in the final productivity of the HNSs, and even the morphologies, being different during the same leaching process. High resolution electron microscopy images obtained during the leaching process gave evidence of a glass-like region and a crystal region coexisting, which was evidence of the ‘path’ formed.