Abstract
It is known that nano-size metal particles have different character and functions from bulk-size metal. With irradiation ultrasound to aqueous solution of noble metal and transition metal cations, metal cations were reduced to metal nanoparticles. We have suggested three different reduction pathways of metal ions under sonication: (i) reduction by H atoms, (ii)reduction by secondary reducing radicals formed by hydrogen abstraction from organic additive with OH radicals and H atoms, (iii)reduction by radicals formed from pyrolysis of the interfacial region between cavitation bubbles and the bulk solution. In this investigation, the solution composed of Fe particles, K_2PtCl_4 solution, and PEG or SDS was sonicated for 2 hours. Products were Fe-Pt bimetallic particles. They have as high hydrogenation catalyst activity as Pt particles
