Electrosynthesis of Single-Crystalline MnOOH Nanorods onto Pt Electrodes

This study concerns the synthesis and fabrication of manganese oxide nanostructures via electrodeposition onto Pt electrodes from aqueous solution of containing . The structural and morphological characterization of the electrodeposited manganese oxide was performed with scanning electron microscopy and high-resolution transmission electron microscopy. These techniques revealed the formation of intersected nanorods of single-crystalline (manganite phase), in agreement with the results of the X-ray diffraction data. Furthermore, a significant enhancement of the electrocatalytic activity of Pt toward the oxygen reduction reaction (ORR) has been observed in -saturated KOH upon the electrodeposition of nanorods. A surface coverage of MnOOH of ca. 0.3 caused a positive shift of the peak potential of the ORR by about compared to that obtained at bare Pt electrode. Similar Tafel slopes were obtained at the bare and the modified Pt electrodes, indicating that the ORR proceeds via the same rate-determining step at the aforementioned electrodes.