The chemistry of bimetallic surfaces – Evolution of an atomic-scale picture

• Structure and stability of bimetallic surfaces are summarized in a common picture • Reactivity is quantitatively correlated with nature/abundance of structural elements • Trends in the reactivity of bimetallic surfaces are summarized in general concepts • They are correlated with the electronic structure using relevant reactivity concepts • Trends are illustrated using well defined PtAg and PdAg bimetallic surfaces In this contribution, we will review the concepts and principles used to characterize and discuss the structure, stability, adsorption properties and catalytic reactivity of bimetallic surfaces in an atomic-scale picture. Starting from early stages, we will emphasize recent experimental and theoretical findings that resulted in a rapidly improving atomic-scale understanding of adsorption and catalytic surface reactions on these surfaces. While examples are often taken from our own work, the resulting insights are of general validity.