C-isolated Ag–C–Co sandwich sphere-nanostructures and their high activity catalysis induced by surface plasmon resonance

Abstract

Magnetic C-isolated Ag–C–Co sandwich sphere nanostructures have been fabricated through a synchronous growth and assembly process, in which the outer Co sphere-shells assemble around the surface of synchronously grown Ag–C sphere-cores. Raman and UV-vis absorption spectroscopy studies show that the covering of Co shell on Ag–C sphere cores weakens the surface-enhanced Raman scattering (SERS) and surface plasmon resonance (SPR) of Ag–C sphere cores. Owing to its ferromagnetic behaviour, the as-prepared C-isolated Ag–C–Co sandwich nanospheres can be easily separated and recycled by an external magnet field for application. Compared with Ag–Co, C–Co, and Co nanospheres of the same size, the resultant magnetic Ag–C–Co sandwich nanospheres exhibit markedly high catalytic activity toward ammonia borane hydrolytic dehydrogenation at atmospheric pressure and room temperature, which is induced by SPR from C-isolated sandwich structural and electronic synergistic effects.