Remarkable electrochemical properties of electrochemically reduced graphene oxide towards oxygen reduction reaction are caused by residual metal-based impurities

Oxygen reduction reaction (ORR) is one of the most important electrochemical reactions in the field of energy storage. Remarkable catalytic properties towards ORR at metal-free electrochemically reduced graphene oxide (ErGO) were previously reported. We demonstrate here that the remarkable enhancement towards ORR of a metal-free ErGO is caused by residual metallic impurities instead of ErGO itself. (c) 2015 Elsevier B.V. All rights reserved.