Preparation and characterization of Ag-Pd bimetallic nano-catalysts in thermosensitive microgel nano-reactor.

Thermosensitive microgels consisting of a solid core of polystyrene and a shell of cross-linked poly( N -isopropylacrylamide) (PNIPA) were synthesized as nano-reactors, in which Ag-Pd bimetallic nanoparticles were prepared through simultaneous in situ reduction reaction. The spatial distribution of metallic nanoparticles in the microgels was analyzed by small angle X-ray scattering (SAXS) and the results indicated that metal nanoparticles were mainly located in the inner layer of microgels. The catalytic activity of Ag-Pd bimetallic nanoparticles was investigated using the reduction of p -nitrophenol to p -aminophenol by NaBH 4 as model reaction. The data demonstrated that Ag-Pd bimetallic nanoparticles showed enhanced catalytic activity compared to each monometallic nanoparticle alone and their catalytic activity was controllable by temperature due to the volume transition of PNIPA microgels.