Oxygen electrocatalysts involving

In Situ Spectroscopic Studies of Oxygen Electrocatalysts Involving Transition Metal Macrocycles... 

For these low-temperature fuel cells, the development of catalytic materials is essential to activate the electrochemical reactions involved. This concerns the electro-oxidation of the fuel (reformate hydrogen containing some traces of CO, which acts as a poisoning species for the anode catalyst methanol and ethanol, which have a relatively low reactivity at low temperatures) and the electroreduction of the oxidant (oxygen), which is still a source of high energy losses (up to 30-40%) due to the low reactivity of oxygen at the best platinum-based electrocatalysts. 

In practice, in all fuel cells that involve the utilization of 02 from air (Section 13.4.5), the oxygen reduction reaction [Eqs. (13.4) and (13.24)] is always rate determining for terrestrial applications. One can seejust how important it is to attempt to develop electrocatalysts for the cathodes of fuel cells on which the enhanced current density is high and Tafel slope is low and the efficiency of energy conversion, therefore, maximal. The direct relation of the mechanism of oxygen reduction and the associated Tafel parameters to the economics of electricity production and transportation is thus clearly seen. 

Mixed-conducting (A,Ln)M03 (M = Fe, Co), promising as cathodes of intermediate-temperature SOFCs, oxygen-separation membranes, and electrocatalysts for high- and low-temperature processes involving oxygen. 

This section describes various strategies for the immobilization of macrocycles on electrode surfaces and their characterization by both electrochemical and in situ spectroscopic techniques in solutions devoid of dioxygen. It also provides theoretical foundations involved in the analysis of the mechanisms of oxygen reduction at such interfaces based on measurements performed under forced convection. Studies involving a number of carefully selected phthalocyanines, and porphyrins, will be presented and discussed, which in our view best illustrate the nuances of the rich behavior this class of adsorbed electrocatalysts can exhibit. These examples serve to... 

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