Electro catalysts interface structure

Electrochemical energy conversion for technical applications relies on a high catalytic reactivity. The electro catalytic reactivity is strongly influenced by the structure and composition of the surface of the catalysts. In PEMFC the catalysts consist of Pt or Pt alloys, which are of nanometer size and often supported on carbon in order to optimize the surface area and the costs of the noble metals. However, the important relation between the reactivity and the structure is obscured in technical electro catalysts by a variety of parameters, like, e.g. the properties of the carbon support, the preconditioning of the catalyst, and the structure of the interface between the electrolyte and the active layer (e.g. the Nafion content). An excellent review on the PEM fuel cell electrodes is given by Litster and McLean (2004)... 

The development of an electrode reaction is highly dependent on the nature of the electrode-solution interface. Most electrochemical processes are still performed using classical metallic or carbon electrodes. However, modifications brought to the surface of the working electrode may result in the enhancement of particular properties which can be exploited in electroanalytical chemistry. In such a way, many electrode materials, such as metals, metal oxides but also carbon based electrodes have been submitted to chemical or non-chemical modifications. Most of the immobilized compounds are electroactive, the electron transfer having to be reversible. They are mainly used as catalysts for electrochemical reactions which cannot be performed at conventional electrodes. In addition, a judicious choice of a catalyst exhibiting a particular structure may also provide more or less specificity towards certain molecules or ions. Electro-inactive substances may also be immobilized and act as intermediates for... 

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