Cyclic voltammetry is used to investigate the electrochemical behaviour of oxide/hydrous oxide formation and reduction as well as that of the Pd(IV)/Pd(II) redox transition at PdO-coated titanium electrodes, the corresponding oxide-derived Pd electrodes, and a bulk Pd metal electrode. X-ray photoelectron spectroscopy (XPS) is used to generate the information of oxidation states for surface Pd ex situ on these PdO and Pd electrodes. The Pd(IV)/Pd(II) redox transition at the PdO-coated titanium electrode possesses an electrocatalytic activity for the ethanol oxidation while this redox transition at the other two Pd electrodes does not.