Silver nanorods for oxygen reduction: Strong effects of protecting ligand on the electrocatalytic activity

Uniform and ultralong silver nanorods are synthesized with a wet chemical reduction method by using PVP as a stabilizer. The crystal structure and morphology of the synthesized nanorods are characterized with transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and UV-vis absorption spectroscopy. The electrocatalytic activity of the Ag nanorods with and without PVP stabilizer, towards oxygen reduction reaction (ORR), is studied and compared by cyclic voltammetry (CV) and rotating disk electrode (RDE) measurements in alkaline solution. Compared to the low current density and incomplete two-electron reaction process of ORR with PVP-protected Ag nanorods, the catalytic activity of the Ag nanorods with removal of the PVP is found to be enhanced remarkably with much higher oxygen reduction current density and the most efficient four-electron process.