IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
capítulos de libros
Título:
Electrochemical electron transfer: from Marcus theory to electrocatalysis
Autor/es:
E. SANTOS; W. SCHMICKLER
Libro:
Fuel Cell Catalysis: a Surface Science Approach
Editorial:
Wiley
Referencias:
Año: 2008;
Resumen:
Electrochemical reactions take place at the interface between an electrode and a solvent, and are governed by the interaction with both. We review the theory for various types of reactions, starting with outer-sphere electron transfer, whose energy of activation is determined by the energy of reorganization of the solvent. Similarly, in the transfer of a simple ion the critical stage is the partial loss of the solvation sheath at the activated state. For bond-breaking transfer in the outer sphere, both the solvent reorganization and the binding energy determine the rate, while the effect of the electrode material is small or even negligible. The situation is entirely different for bond-breaking electron transfer on the electrode surface; there, a good electrode catalysts can lower the energy of activation drastically. We present a theory for the course of such reactions, which explains how a good catalysts acts. In particular, it illustrates the role played by a d band near the Fermi energy, and it points out the important parameters which govern such reactions.d band near the Fermi energy, and it points out the important parameters which govern such reactions.