This study quantitatively elucidates the role of the metal clusters in the electrochemical activation of the metal oxide nanostructured electrodes. Through the deposition of nearly mono-dispersed AuxPt1-x (x= 0, 0.5, 1) clusters, smaller than 3 nm, on the ZnO NanoRod (NR) electrode surface, a controlled enhancement of charge transfer and activation of electro-catalytic processes is achieved. The interfacial electrical states of the hybrid electrodes were probed by electrochemical impedance spectroscopy (EIS). Charge- ...