Au, Ag and Au-Ag nanoparticles: microwave-assisted synthesis in water and applications in ceramic and catalysis

A simple, microwave-assisted route for producing Au/Ag concentred sols by glucose reduction in water was developed. Ag-Au bimetallic nanoparticles stabilized by polyvinylpyrrolidone (PVP) were characterized and their catalytic activity was studied in the reduction of 4nitrophenol (4-NP) with NaBH4. Moreover they were tested as red ceramic inks for ink-jet printing technology. Since the research was developed in collaboration with a company interested in the large scale production of the suspensions, some fundamental properties for an industrial scale up were developed: high metal concentration, long time stability. The Au-Ag core-shell structures were prepared by a two-step process. Particle size-control and colloidal stability were achieved thanks to the accurate reaction optimization, combined with microwave heating, that allows the intensification of process even on large scale production. Prepared Au, Ag and Au/Ag nanocrystals acted as effective catalyst for the reduction of 4-NP.