Palladium shell of ~11 to 15 nm thickness has been synthesized successfully by reduction of surface bound palladium ions onto ~200 nm diameter silica core. The method for generating such nanoshells is based on seed-mediated growth technique. Palladium ions from complex palladium salt are adsorbed onto aminosilane functionalized silica core and subsequently reduce to create <i>in situ</i> palladium nanoparticle seeds. These nanoparticle seeds act as the nucleation sites to promote further growth of final palladium overlayer. Palladium nanoparticle seeds generated onto the functionalized silica surface are ~3nm in diameter and are uniformly distributed throughout the core surface as observed by transmission electron microscopy (TEM). The thickness of the final palladium shell can easily be tailored by varying the concentration of the seeded core during the shell formation step. An increase concentration of seeded core leads to decrease in shell thickness. In addition, use of ascorbic acid generates uniform shell compare to formaldehyde as reducing agent. The formation of the palladium nanoshells is extensively monitored using ultraviolet-visible spectroscopy and TEM, with zeta potential measurement to assess the surface charge of silica core and after surface functionalization. This present method reports the first time synthesis of palladium nanoshell from surface bound palladium nanoparticle seeds compare to all the earlier reports that use gold nanoparticle as seed to generate the final palladium shell.

Palladium nanoparticle seed mediated growth of palladium nanoshell on silica core

251st National Meeting (2016)

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