Atomic layer deposition of nanoalloys of noble and non-noble metals

We present a novel ALD-based approach for the synthesis of bimetallic materials consisting of a noble metal along with a nonnoble metal such as Pt-M (M = In, Ga, Sn, etc.), with a precise control on the composition and size. First, a bilayer consisting of a metal oxide and a Pt film of the desired thickness is deposited on to the substrate. The film is then subjected to a temperature programmed reduction (TPR) under H2 atmosphere. In situ X-ray diffraction (XRD) measurements during TPR revealed the formation of Pt±M bimetallic alloys with a phase determined by the Pt/(Pt + M) atomic ratio of the as-deposited bilayer. Scanning electron microscopic (SEM) analysis revealed the formation nanoparticles after annealing, with the particle size controlled by the initial total thickness of the bilayer.