An unconventional mechanism of hollow nanorod formation: asymmetric Cu diffusion in Au-Cu alloy nanorods during galvanic replacement reaction.

This study investigates how AuCu3 alloy nanorods transform into hollow rods during a galvanic replacement reaction. An unusual reaction intermediate was observed where the solid nanorod became partially hollow and Cu rich at one end. This was attributed to simultaneous galvanic replacement and asymmetric diffusion of Cu due to the Kirkendall effect. The hollow Au-Cu nanorods showed enhanced catalytic activity for p-nitrophenol reduction.