Electrocatalysis oxygen cathodic reduction

Electrocatalysis in fuel cells requires as well substances capable of catalyzing the anodic oxidation of fuels as catalysts for the cathodic reduction of oxygen. Several dyestuffs that catalyze oxygen reduction are known, but up to now only one has been described as active in anodic reactions. All these dyestuffs are N4-chelates. 

V. Electrocatalysis of Cathodic Oxygen Reduction and Anodic Hydrogen Oxidation in Fuel Cells... 

Elzing, A., A. van der Putten, W. Visscher, and E. Barendrecht (1987). The cathodic reduction of oxygen at metal tetrasulfonato-phthalocyanines Influence of adsorption conditions on electrocatalysis. J. Electmanal. Chem. 233, 99-112. 

Elzing A, van der Putten A, Visscher W, Barendrecht E (1986) The cathodic reduction of oxygen at cobalt phthalocyanine. Influence of electrode preparation on electrocatalysis. J Electroanal Chem 200(l-2) 313-322... 

ELECTROCATALYSIS OF OXYGEN REDUCTION IN THE FUEL CELL CATHODE NEW INSIGHTS AND NEW OUESTIONS... 

ELECTROCATALYSIS OE OXYGEN REDUCTION IN THE EUEL CELL CATHODE... 

Also for cathodic oxygen reduction in low-temperature fuel cells, platinum is indispensible as a catalyst whereas the cathodic electrocatalysts in MCFCs and SOFCs are lithiated nickel oxide and lanthanum-manganese per-ovskite, respectively. Appleby and Foulkes in the Fuel Cell Handbook (101) reviewed the fundamental work as well as the technologically important publications covering electrocatalysis in fuel cells till 1989. 

The Electrocatalysis of Oxygen Reduction at Fuel Cell Cathodes... 

E25.17 Electrocatalysts are compounds that are capable of reducing the kinetic barrier for electrochemical reactions (barrier known as overpotential). While platinum is the most efficient electrocatalyst for accelerating oxygen reduction at the fuel cell cathode, it is expensive (recall Section 25.18 Electrocatalysis). Current research is focused on the efficiency of a platinum monolayer by placing it on a stable metal or alloy clusters your book mentions the use of the alloy PtsN. An example would be a platinum monolayer fuel-cell anode electrocatalyst, which consists of ruthenium nanoparticles with a sub-monolayer of platinum. Other areas of research include using tethered metalloporphyrin complexes for oxygen activation and subsequent reduction. 

Alloys of noble metals have been tested for O2 reduction [31] and some should even be more efficient than Pt [63]. These metals are expensive so that other materials have been tested, like bronze, some being even slightly better electrocatalysis than platinum [45] however, they do not seem to be stable enough. The factors governing oxygen reduction on oxides used as cathodes in fuel cells have been reviewed recently [92]. 

K. Wiesener and D. Ohms, "Electrochemical Hydrogen Technologies Cap. 3 - Electrocatalysis of the Cathodic Oxygen Reduction", Ed. H. Wendt, Elsevier, Amsterdam, 1990 63-103. 

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