Stability of nanostructured silver-platinum alloys

The stability of Ag-Pt systems: 13-atoms icosahedral cluster model (Ag 13-nPt n) and 54-atoms (111) surface slab model (45Ag9Pt) have been systematically investigated by using Density Functional Theory within the generalized gradient approximation (DFT–GGA). Experimentally tested resistance of AgPt alloy nanoparticles supported on silica to decay upon temperature treatment (423 K–573 K in N 2 flow) have shown to correlate with theoretical results. The stability of the clusters as a function of AgPt composition decreases with increasing content of Pt. The general stability trend of the AgPt alloy was maintained, in theory and experiment, for the Ag/Pt molar ratio of 1.6–5.1. Two particularly stable Ag/Pt compositions were revealed: 1.6 and 0.4. It was also found that surface location of platinum is responsible for stabilization of the Ag-Pt nanostructured alloy.