Dopamine-Directed In-Situ and One-Step Synthesis of Au@Ag Core-Shell Nanoparticles Immobilized to a Metal-Organic Framework for Synergistic Catalysis

We report a facile and general approach to the formation of bimetallic core-shell Au@Ag nanoparticles (NPs) immobilized to metal-organic frameworks (MOFs) via a one-step synthetic route at room temperature. Dopamine (DA) is used as a moderate reductant, which can bind to negatively charged groups of MOFs through electrostatic interaction, and subsequently Au@Ag core-shell NPs are formed by in-situ reduction of the bimetallic Au and Ag precursors step-by-step spontaneously without pre-synthesized seeds. The as-formed Au@Ag core-shell NPs immobilized to MOFs exhibit excellent catalytic activity for the reduction of 4-nitrophenol (4-NPh) by NaBH4 to 4-aminophenol (4-APh) due to a synergistic effect and are highly stable as demonstrated by recycling experiments.