(474c) Rational Design of Alloy Catalysts

The activity, selectivity, and stability of alloy catalysts can be optimized by tailoring their composition, shape, and atomic order. However this same compositional and structural flexibility makes it difficult to predict the structure and catalytic properties of alloys from first principles. We will demonstrate how the cluster expansion method can be used to explore the vast space of possible alloy structures and nanostructures with a level of accuracy close to density functional theory, enabling the rational design of alloy catalysts. Examples will be drawn from catalysts for the oxygen reduction reaction, but the methods we present can be applied to alloy catalysts for a variety of chemical reactions. We will introduce a method for generating surface cluster expansions that are dependent on the lattice parameter of the material and demonstrate how this approach can be used to create complete maps of catalytic activity for thermodynamically stable phases across compositions and temperatures, making it possible to identify the synthesis conditions likely to produce the most active catalysts. By analyzing these maps, we will discuss in particular the role of bulk atomic order in determining the catalytic activity of alloy surfaces.