Authors: M. Blosi, S. Ortelli, S. Albonetti, A.L. Costa, L. Ortolani, M. Dondi
Affilation: Istec-CNR, Italy
Pages: 327 - 330
Keywords: colloidal nanosols, green synthesis, microwave, noble metals, bimetals
We report an environmentally benign approach to the production of stable metals nanosols. Water has been chosen as benign solvent, glucose serve as a mild, renewable and non-toxic reducing agents and microwave irradiation was used as heating method. Bimetallic nanoparticles with various noble metals (AuCu, AuAg, PdCu, AuPd) as well as the respective monometallic nanoparticles were synthesized following the developed strategy. A deep characterization was performed using HR-TEM, XEDS, UV-vis spectra, XRD, and TG analysis. This synthesis route showed several advantages with respect to other methods, in fact it is simple, eco-friendly, carried out at low temperature and easily scalble. Particle size-control, total reaction yield, high solid loading and long time stability of colloids, were achieved thanks to an accurate reaction optimization. HRTEM analysis indicated that prepared nanoparticles are typically spherical and polycrystalline, with mean diameters ranging from 2 to 10 nm, depending on particle composition. Electron diffraction and XRD analyses evidenced the formation of alloy or core-shell structures. Prepared nanoparticles acted as excellent catalysts in the reduction of 4-nitrophenol with NaBH4, tested as a probe reaction. Moreover supported catalysts were prepared by immobilization of these preformed monometallic and bimetallic colloids.