Figure 4.
(A) TEM image of nanoboxes obtained by galvanic replacement reaction between 50-nm Ag nanocubes and 10 mL of 0.2 mM HAuCl4 solution. After etching with (B) 10, (C) 20, and (D) 100 μL of 50 mM aqueous Fe(NO3)3 solution, no significant morphological change was observed. EDX analysis shows that the atomic ratios of Au to Ag are 30:70, 36:64, 40:60, and 43:57 for (A), (B), (C), and (D), respectively.