The O-2(g),Pt/YSZ system was characterized at 450 degrees C by using various electrochemical techniques such as single- and double-step chronoamperometry, chronocoulometry and chronopotentiometry. The response to these experiments gives evidence for the presence of pseudocapacitive processes related with charge storage. Linear sweep voltammetric measurements after prolonged anodic polarization have shown that these charges are located at three different locations. (C) 2007 Elsevier Ltd. All rights reserved.