The Role of Lone-Pair Electrons in Pt-N Interactions for the Oxygen Reduction Reaction in Polymer Exchange Membrane Fuel Cells.

An N-doped carbon with various N concentrations was prepared by using a scalable ball-milling method. The importance of the lone pair of electrons on the N species for the stability of Pt nanoparticles and their activity toward the oxygen reduction reaction was investigated. X-ray spectroscopic analysis was used to investigate the interaction between Pt and the pyridinic N. The pyridinic N modified the Pt oxidation state and helped achieve size homogeneity and high catalytic activity by facilitating the rate-determining step.