Green synthesis of noble metal and bimetal nanosols and their applications as catalysts

Bimetallic nanoparticles with various noble metals (AuCu, AuAg, PdCu, PdAu) as well as the respective monometallic nanoparticles protected by PVP shell were synthesized following the developed strategy. A deep characterization was performed on prepared sols using HR-TEM, XEDS, UV-vis, ICP-OES and XRD. Microwave heating has been shown to provide more homogeneous particle nucleation and shorter synthesis time than traditional heating. This synthesis route showed several advantages with respect to other methods, in fact it is simple, eco-friendly, carried out at low temperature and easy transferable on large scale production. Particle size-control, total reaction yield, high solid loading and long time stability of colloids, were achieved thanks to an accurate reaction optimization. Prepared nanoparticles acted as effective catalysts in the reduction of 4-nitrophenol with NaBH4, a typical probe reaction.