Electroactive platinum surface area

Electrochemical kinetics confined to TPB For platinum, the important chemical processes of catalytic reduction and transport occur on the Pt surface, and thus the electroactive species formed are most readily available near the Pt-surfaceA SZ interface (TPB). Although it is not entirely clear how these electroactive species are subsequently incorporated into the electrolyte bulk or what role the electrolyte itself plays in this process, there is strong circumstantial evidence that the electrochemical—kinetic step is restricted to an area close to the TPB. Unfortunately very little is known about the nature of this reaction since the details are often obscured by chemical effects involving the Pt surface. 

---