Film Electrocatalytic Effects in Photoelectrolysis Processes

Metal Film Electrocatalytic Effects In Photoelectrolysis Processes 

It had not been realized until recently that electrocatalysis in the water decomposition processes at photoactive semiconductor electrodes was as important as the band-structure properties of the semiconductor material itself. However, it is clear that the effective voltage, beyond the 1.23 V limit, or 1.23 F - hv, required to photoelectrolyze water at some net rate will also be determined, as with metals, by the electrocatalytic properties of the semiconductor surfaces. 

Many semiconductor materials, by themselves, are not good electrocatalysts for Hz or Oz evolution, and in the photoanode reaction some dissolution or corrosion of the semiconductor itself is a common problem. It was proposed and shown by Bockris et al. (204) that major improvements in photoelectrolysis of water could be achieved, from the kinetic point of view, by preparing the semiconductors with thin coatings of electrocatalysts appropriate to the respective cathodic or anodic reactions involved such 

Electrocatalysis and Kinetic Behavior of Oxygen Evolution Reaction 

One of the most extensively examined gas evolution reactions, next only to the H2 evolution reaction, is the O2 evolution reaction (OER) (209) as it is one of the main electrochemical reactions in water electrolysis, metal electrowinning, and recharging of metal-air cells. The standard electrode potential for the oxygen evolution reaction at 25°C calculated from the standard Gibbs energy of formation of H2O and OH ions (/) is 1.299 V [versus normal H2 electrode (NHE)] and 0.401 V (versus NHE) in alkaline media. The oxygen evolution reactions are 

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XVI. Metal Film Electrocatalytic Effects In Photoelectrolysis Processes... 

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