Electrochemical Oxygen Reduction on Metal-Free Nitrogen-Doped Graphene Foam in Acidic Media

Abstract

Non-precious oxygen reduction reaction (ORR) catalysts could help reduce the cost of future generations of polymer electrolyte membrane fuel cells (PEFCs). One class of Pt-free catalysts for PEFCs are nanostructured Fe/C/N-based materials. In these, the nature of the active site is still hotly contested. Resolving this issue could lead to the development of better catalysts. One approach to achieve this is to study nitrogen-doped carbons which do not contain any Fe. Such materials have been studied, but largely in alkaline media where high activity is obtained. To truly understand the ORR mechanism of Fe/C/N-based catalysts, measurements in acid media are required to simulate the activity in proton-based PEFC systems. Here we present bulk synthesis of a metal-free nitrogen-doped graphene powder with remarkable surface area. We apply this as an ORR catalyst in acid media and comment on the reaction mechanism.