Incipient hydrous oxide/adatom mediator

The formation of Au-OHad or surface oxides on gold in alkaline electrolyte was in fact proposed to explain some of the electrocatalytic properties observed for a gold electrode (e.g., incipient hydrous oxide/adatom mediator model ). Our previous measurement of the interfacial mass change also indicated the formation of Au oxides (AU2O3, AuOHorAu(OH)3) on gold nanoparticle surfaces. A detailed delineation of the catalytic mechanism is part of our on-going work. 

An interesting, although controversial, development in this field is the new approach outlined in recent papers by Burke et al. that is referred to by the author as Incipient Hydrous Oxide-Adatom Mediator (IHOAM) model. 

Because gold displays very weak chemisorbing properties, the activated chemisorption model of electrocatalysis is assumed to be inapplicable in the case of this metal in aqueous media. The alternative, which is well established in the chemically modified electrode [48] and redox sensor [49] area, is the interfacial cyclic redox mediator model which, in the case of gold in aqueous media, is sometimes referred to as the incipient hydrous oxide/adatom mediator (IHOAM) [18,33] model. In the case of the Group 11 metals the mediator systems are unusual in that their redox transitions involve couples with nonequilibrium (or metastable) reduced and oxidized states. 

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