Enhanced water electrolysis: Electrocatalytic generation of oxygen gas at manganese oxide nanorods modified electrodes

This study is concerned with the electrocatalytic evolution of oxygen gas at manganese oxide nanorods modified Pt, Au and GC electrodes in 0.5 M KOH solution. The electrochemical measurements revealed a significant enhancement of the electrocatalytic activity of the Pt, Au and GC electrodes towards the oxygen evolution reaction (OER) upon the electrodeposition of manganese oxide nanoparticles (nano-MnOx), that is, the onset potentials of the OER at the modified Pt, Au and GC electrodes are more negative by about 300, 550 and 300 mV, respectively, compared with the bare (i.e., unmodified) electrodes. MnOx is electrodeposited in a porous nano-texture structure which covers the entire surface of the substrates homogeneously. The MnOx of a single crystalline manganite phase (gamma-MnOOH) plays a vital role as a catalytic mediator, which facilitates the charge transfer during the water oxidation into molecular oxygen and thus the OER is accomplished at less positive potentials. (C) 2007 Elsevier B.V. All rights reserved.