Mechanochemically obtained Pd–Ag nanoalloys. Structural considerations and catalytic activity

The nanostructured alloys of the Pd–Ag system have shown outstanding properties due to the synergistic effects of the alloying; additionally, it is a system that meets very well the Hume–Rothery rules for alloys formation and hence, shows complete miscibility at all compositions, especially at the nanoscale. Consequently, several synthetic routes have been already explored. In this work a novel and relatively low cost mechanochemical synthetic route to obtain nanoparticles of this bimetallic system is presented. The entire characterization suggests the formation of a nanostructured alloy in all samples, as well as, the lack of segregated pure metals. Suzuki–Miyaura cross-coupling reaction was used as model reaction in order to evaluate the catalytic activity of the synthesized Pd100-xAgx alloys, which have behaved as an excellent heterogeneous ligand-free catalyst. The reaction can be achieved under mild conditions, with low catalyst loadings; these catalysts also maintained most of their activity after successive catalytic cycles with high yields. Furthermore, the observed activity seems to be due not only to Pd content, but to the nanoalloy is having a role in the catalytic process. Therefore, the cost of the catalytic reaction could be reduced by using PdAg nanoalloys.