Catecholamine-Induced Electroless Metallization of Silver on Silica@Polymer Hybrid Nanospheres and Their Catalytic Applications

Narrowly dispersed raspberry-like SiO2@poly(dopamine acrylamide-co-methacrylic acid-co-ethylene glycol dimethacrylate)/Ag (or SiO(2)PDA/Ag) composite nanospheres were synthesized via a combination of sol-gel reaction, distillation-precipitation polymerization, reactive ester-amine reaction, and electroless metallization. In this approach, SiO2@poly(pentafluorophenyl acrylate-co-methacrylic acid-co-ethylene glycol dimethacrylate) (or SiO2@PPFA) core-shell nano-spheres were first prepared by distillation-precipitation polymerization, using the SiO2-3-(trimethoxysilyl)propyl methacrylate (SiO2-MPS) nanospheres from sol-gel reaction as seeds. The reactive pentafluorophenyl (PFP) ester moieties on SiO2@PPFA nanospheres can readily react with dopamine hydrochloride to form amide linkages with no side reaction under a mild condition. The catecholamine moieties in the resulting SiO2@PDA nanospheres were utilized for simultaneous reduction of Ag+ ions and coordinative binding of the metal nanoparticles. The SiO2-MPS, SiO2@PPFA, and SiO2@PDA nanospheres as well as the raspberry-like SiO2@PDA/Ag composite nanospheres were characterized by field-emission transmission electron microscopy (FETEM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), X-ray photoelectron spectroscopy (XPS), and FT-IR spectroscopy. Furthermore, the as-synthesized SiO2@PDA/Ag composite nanospheres were explored for the catalytic reduction of p-nitrophenol and degradation of rhodamine 6G (R6G) dye.