Electrocatalysis activation barriers

The presence of solution or solvent can appreciably perturb the chemistry of surface-catalyzed reactions compared to their ultra-high vacuum or vapor-phase counterparts. Polar solvents, such as water, are able to stabilize charged intermediate and transition-state species at the surface that are unstable (or less stable) as gas-phase adsorbates, thus altering both the thermodynamics (i.e., reaction energy) and kineties (i.e., activation barrier) for specific reaction steps. This can influence the activity, as well as the selectivity of the overall catalytic system, and thus control aqueous-phase electrocatalysis. Thiel and Madey [36] and Henderson [37] present exceptional reviews that describe in... 

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. 

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