Using a Macroporous Silver Shell to Coat Sulfonic Acid Group-Functionalized Silica Spheres and Their Applications in Catalysis and Surface-Enhanced Raman Scattering
2015
Ren, Guohong | Wang, Wenqin | Shang, Mengying | Zou, Hanzhi | Cheng, Shengwei
In this paper, novel organic sulfonic acid group-functionalized silica spheres (SiO₂–SO₃H) were chosen as a template for fabricating core–shell SiO₂–SO₃H@Ag composite spheres by the seed-mediated growth method. The SiO₂–SO₃H spheres could be obtained easily by oxidation of the thiol group-terminated silica spheres (SiO₂–SH) with H₂O₂. Due to the presence of sulfonic acid groups, the [Ag(NH₃)₂]⁺ ions were captured on the surface of the silica spheres, followed by in-site reduction to silver nanoseeds for further growth of the silver shell. By this strategy, the complete silver shell could be obtained, and the surface morphologies and structures of the silver shell could be controlled by adjusting the number of sulfonic acid groups on the silica spheres. A large number of sulfonic acid groups on the SiO₂–SO₃H spheres favored the formation of the macroporous silver shell, which was unique and exhibited good catalytic performance and a high surface-enhanced Raman scattering (SERS) enhancement ability.
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