Electrodeposited MnO_<i>x</i>/PEDOT Composite Thin Films for the Oxygen Reduction Reaction

Manganese oxide (MnO_<i>x</i>) was anodically coelectrodeposited with poly­(3,4-ethylenedioxythiophene) (PEDOT) from an aqueous solution of Mn­(OAc)₂, 3,4-ethylenedioxythiophene, LiClO₄ and sodium dodecyl sulfate to yield a MnO_<i>x</i>/PEDOT composite thin film. The MnO_<i>x</i>/PEDOT film showed significant improvement over the MnO_<i>x</i> only and PEDOT only films for the oxygen reduction reaction, with a >0.2 V decrease in onset and half-wave overpotential and >1.5 times increase in current density. Furthermore, the MnO_<i>x</i>/PEDOT films were competitive with commercial benchmark 20% Pt/C, outperforming it in the half-wave ORR region and exhibiting better electrocatalytic selectivity for the oxygen reduction reaction upon methanol exposure. The high activity of the MnO_<i>x</i>/PEDOT composite is attributed to synergistic charge transfer capabilities, attained by coelectrodepositing MnO_<i>x</i> with a conductive polymer while simultaneously achieving intimate substrate contact