The Brønsted-Evans-Polanyi Relation and the Volcano Plot for Ammonia Synthesis over Transition Metal Catalysts. The Brønsted-Evans-Polanyi Relation and the Volcano Plot for Ammonia Synthesis over Transition Metal Catalysts. =============================================================================================================== by A. Logadottir, T. H. Rod, J. K. Norskov, B. Hammer, S. Dahl, and C. J. H. Jacobsen. Abstract -------- Using density functional calculations we show that there is an essentially linear relationship between the activation energy for N2 dissociation and the binding energy of atomic nitrogen on a range of transition metal surfaces. This relation, known as the Brønsted-Evans-Polanyi relation, is further shown to depend on the structure of the active site. The consequence of the Brønsted-Evans-Polanyi relation in terms of the kinetics of the ammonia synthesis process under industrial conditions are discussed, and it is shown that the relation leads to a volcano-type dependence of the catalytic activity on the nitrogen heat of adsorption. The result show that density functional calculations can predict the relative catalytic activity of different transition metals.