Manganese oxide nanoparticles supported nitrogen-doped graphene: a durable alkaline oxygen reduction electrocatalyst

Abstract

Manganese oxide-based nitrogen-doped reduced graphene oxide (MnO/N-rGO) electrocatalyst was developed by a simple sol–gel process with aqueous KMnO4 and sucrose by adding nitrogen-doped reduced graphene oxide. The physical characterizations were systematically evaluated by X-ray diffraction, field emission scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscopy. The electrochemical and oxygen reduction properties of the electrocatalyst and support were studied by employing cyclic voltammetry and linear sweep voltammetry techniques on a rotating-disk electrode in alkaline (0.1 M KOH) solution and compared with commercial Pt/C catalysts. The synthesized catalyst possesses a high oxygen reduction activity and the rotating ring-disk electrode results illustrate a 3.8 e− transfer process. Stability tests performed for 10,000 potential cycles exhibited that the MnO/N-rGO catalyst is more durable than Pt/C catalyst. MnO/N-rGO as cathode catalyst in a single alkaline fuel cell studies gave a peak power density of 44 mW cm− 2 at 40 °C. Durability by accelerated stress test (AST) in fuel cell mode demonstrated MnO/N-rGO as alternative hybrid cathode catalyst which has excellent stability and durability of 67% more than commercial Pt/C.