The effects of both pH and temperature on the kinetics of redox processes that involve the charging/discharging of electrocatalytic sites, at dimensionally stable anodes, have been investigated. At first, electrodes based on Ir and Sn oxides, having different molar compositions, were studied by X-ray diffraction in order to characterize the system under investigation, and with the four-probe method to evaluate how the film resistivity varies with the oxide composition. Then, cyclic voltammetric experiments were carried out at different temperatures to estimate the apparent activation energy (W-a) of the charging/discharging process of active sites. The W-a values obtained were rather low (about 0.5 kcal mol (1)) and thus realistically not attributable to any chemical reaction. By excluding a role for the various physicochemical parameters that could influence the process, we suggest that the "double injection/double ejection" mechanism is related to a Grotthuss-type movement of protons, which takes its advantage from an electrode-electrolyte interface extending for a few monolayers within the oxide coating. The interface thus represents a relatively rigid and organized structure in which protons can move without any hindrance. (C) 2014 Elsevier Ltd. All rights reserved.