Enhanced Oxygen Reduction Reaction Activity with Electrodeposited Ag on Manganese Oxide-Graphene Supported Electrocatalyst

Manganese oxide-modified graphene nanosheet-supported silver nanocatalyst (Ag-MnOx/G) was prepared via two-step chemical and electrochemical deposition. Surface characterization of the prepared Ag-MnOx/G catalyst was performed by X-ray photoelectron spectroscopy, scanning electron microscopy, as well as X-ray fluorescence techniques, and the electrocatalytic activity toward the oxygen reduction reaction (ORR) in alkaline media was studied using cyclic voltammetry and the rotating disk electrode (RDE) method. The onset potential of the ORR of the prepared catalyst material shifted positive about 40 mV, and the half-wave potential 20 mV compared to those of the bulk Ag electrode. After 1000 potential cycles between 0.05 and 1.1 V for accelerated aging tests, high stability of the Ag-MnOx/G catalyst in the ORR was observed with the half-wave potential of the ORR shifting negatively only about 0.04 V. RDE studies displayed unconditional improvement of electrochemical activity and long-term durability for the Ag-MnOx/G composite material.