Br0nsted-Evans-Polanyi relation

Bligaard T, Nprskov JK, Dahl S, Matthiesen J, Chistensen CH, Sehested J. 2004. The Br0nsted-Evans-Polanyi relation and the volcano curve in heterogeneous catalysis. J Catal 224 206-217. 

Logadottir A, Rod TH, N0rskov JK, Hammer B, Dahl S, Jacobsen CJH. 2001. The Br0nsted-Evans-Polanyi relation and the volcano plot for ammonia synthesis over transition metal catalysts. J Catal 197 229. 

Table 3.4. CO transition-state energies according to the Br0nsted—Evans-Polanyi relation (kJ/mol).

The Br0nsted-Evans-Polanyi relation applied to the CO dissociation reaction results in Table 3.4. The quantum-chemical result upon which this is based is the dissociation of CO over Ru(OOOl) with 2x2 coverage. 

Loffreda D, Delbecq F, Vigne F, Sautet P. Fast prediction of selectivity in heterogeneous catalysis from extended Br0nsted-Evans-Polanyi relations A theoretical insight. Angew Chem Int Ed 2009 48 8978-8980. 

We use the constructs of transition state theory in order to define the Br0nsted-Evans-Polanyi (BEP) relationship, which relates the equilibrium thermodynamics (reaction enthalpy or free energy) with non-equilibrium thermodynamic features, namely the activation energy and activation entropy. A small value of the proportionality parameter in the BEP relationship, a, is identified with an early transition state, whereas values of a that are close to 1 relate to a late transition state. Microscopic reversibility ensures that if the forward reaction is an early transition state then the backward reaction must be a late transition state and vice versa. 

According to the empiric Br0nsted-Evans-Polanyi (BEP) relation, the activation energy for dissociation of a molecule is a linear function of the chemisorption energy of the atoms of the dissociated molecule ... 

Transition state properties cannot be directly estimated from this method. To do this, as mentioned in Chapter 3, Br0nsted—Evans—Polanyi relationships are appHed relating kinetics with thermochemical properties. Such relationships use correlations developed from similar reactions belonging to the same homologous series. 

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