“Metal-free” catalytic oxygen reduction reaction on heteroatom-doped graphene is caused by trace metal impurities

• Main Authors: Wang, Lu, Ambrosi, Adriano, Pumera, Martin
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Materials::Nanostructured materials
• Online Access: https://hdl.handle.net/10356/102022; http://hdl.handle.net/10220/18915
• Institution: Nanyang Technological University

The oxygen reduction reaction (ORR) is of high industrial importance. There is a large body of literature showing that metal-based catalytic nanoparticles (e.g. Co, Mn, Fe or hybrid Mn/Co-based nanoparticles) supported on graphene act as efficient catalysts for the ORR. A significant research effort is also directed to the so-called “metal-free” oxygen reduction reaction on heteroatom-doped graphene surfaces. While such studies of the ORR on nonmetallic heteroatom-doped graphene are advertised as “metal-free” there is typically no sufficient effort to characterize the doped materials to verify that they are indeed free of any trace metal. Here we argue that the claimed “metal-free” electrocatalysis of the oxygen reduction reaction on heteroatom-doped graphene is caused by metallic impurities present within the graphene materials.