Portal de Periódicos da CAPES

On the behavior of Brønsted-Evans-Polanyi relations for transition metal oxides

2011; American Institute of Physics; Volume: 134; Issue: 24 Linguagem: Inglês

10.1063/1.3602323

1520-9032

Aleksandra Vojvodić, Federico Calle‐Vallejo, Wei Guo, S. Wang, Anja Toftelund, Felix Studt, José I. Martínez, Juan Shen, Isabela C. Man, Jan Rossmeisl, Thomas Bligaard, Jens K. Nørskov, Frank Abild‐Pedersen,

Thermal and Kinetic Analysis

Versatile Brønsted-Evans-Polanyi (BEP) relations are found from density functional theory for a wide range of transition metal oxides including rutiles and perovskites. For oxides, the relation depends on the type of oxide, the active site, and the dissociating molecule. The slope of the BEP relation is strongly coupled to the adsorbate geometry in the transition state. If it is final state-like the dissociative chemisorption energy can be considered as a descriptor for the dissociation. If it is initial state-like, on the other hand, the dissociative chemisorption energy is not suitable as descriptor for the dissociation. Dissociation of molecules with strong intramolecular bonds belong to the former and molecules with weak intramolecular bonds to the latter group. We show, for the prototype system La-perovskites, that there is a "cyclic" behavior in the transition state characteristics upon change of the active transition metal of the oxide.