Impurities in graphenes and carbon nanotubes and their influence on the redox properties

Carbon nanomaterials, such as carbon nanotubes and graphene-related materials are currently being heavily researched and widely proposed for numerous applications. It is often underestimated that these carbon nanomaterials are of complex nature, consisting of different components and often containing impurities. These impurities can dramatically influence, or even dominate various properties of carbon nanotubes and graphenes. Herein, we will show that impurities in such carbon nanomaterials are capable of exhibiting a striking effect on their redox properties. The impurities being discussed include metallic, nanographitic and amorphous carbon-based impurities commonly found in carbon nanotube samples; and metallic, nanographitic, and carbonaceous debris-based impurities in graphenes. We emphasize that the effects brought about by these impurities on the properties of the carbon nanomaterials can, in many cases be rather significant. As such, one needs to be cautious by clearly accounting for these effects observed for the nanomaterials before assigning any properties to the material itself.