Figure 1.

Etching of Au@SiO₂ NRs with and without CTAB in the mesopores (a–d) Schematic representation and corresponding TEM images of the etching process of the Au@SiO₂ NRs with CTAB (a, b) and without CTAB (c, d) in the mesopores after 10 and 25 min of etching in methanol containing 0.24 M HCl and 50 mM H₂O₂. (e) Extinction spectra of the Au@SiO₂ NRs in MeOH during etching with 50 mM H₂O₂ and 0.24 M HCl. (f) LSPR peak position during etching with 0 mM HCl and 0 mM H₂O₂ (brown) and 0, 20, 50, and 100 mM H₂O₂ with 0.24 M HCl in MeOH at 60 °C. (g) LSPR peak position during etching at 50, 60, and 70 °C with [H₂O₂] = 50 mM. The data in (b, e–g) were acquired for the etching process of the Au@SiO₂ NRs with CTAB in the mesopores.