Oxygen Activation for Fuel Cell and Electrochemical Process Applications

Oxygen Activation for Fuel Cell and Electrochemical Process Applications 

This chapter aims at describing the main issues for the activation of molecular and atomic oxygen in electrochemical processes. The electroreduction of molecular oxygen has important applications in the energy conversion domain (i.e. fuel cells and metal-air batteries), in electrosynthesis reactors and in the chlor-alkali process. 

The electro-oxidation of organic compounds, for the electrosynthesis process, fuel cell or sensor applications, necessitates an efficient activation of the oxygen atom of water, which will be the second aspect of this chapter. 

The electrocatalytic activation of oxygen is of great importance in several electrochemical systems and processes such as fuel cells, metal-air batteries, the chlor-alkali process, electrosynthesis reactors, etc. 

In fuel cells working with a liquid fuel, usually an alcohol such as methanol (a direct methanol fuel cell - DMFC), ethanol (a direct ethanol fuel cell - DEFC), glycerol (a direct glycerol fuel cell - DGEC), etc., in addition to the necessity to activate the ORR at the cathode, the alcohol oxidation reaction at the anode also involves a high overpotential. This high overpotential is mainly due to the formation, after dissociative adsorption of the alcohol at the catalyst surface, of poisoning species which block the catalytic surface the main one adsorbed is carbon monoxide.  

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