Plasma-Assisted Nitrogen Doping of Ketjen Black to Promote Electrocatalytic Oxygen Reduction Reaction

Nitrogen-doped carbon materials show promising prospects in enhancing the efficiency of cathodic oxygen reduction reactions. Compared to the traditional chemical methods, the dry processing by discharge plasma provides an efficient and ecofriendly modification method for higher catalyst activity. In this paper, we report on the morphology, structure, and elemental distribution of nitrogen-doped Ketjen Black which is modified by Ar/O2 surface dielectric barrier discharge at atmospheric pressure. Special attention is paid to the evaluation of oxygen reduction. Results show that the plasma can rapidly realize nitrogen doping in the process of forming new bonds. Additionally, oxygen reduction activity is enhanced by plasma etching via increasing the catalyst surface area and exposing more active sites. The doped nitrogen which appears as mainly graphitic N is more conducive to enhancing the activity of oxygen reduction reactions. This dry and efficient plasma method is expected to improve the reaction activity of the oxygen reduction catalyst in fuel cells.