Non‐Chemical Route to PGM‐Free via N+ Ion Implantation in Vertically Aligned Carbon Nanotubes

Abstract The continuous research on electrocatalytic nanomaterials for critical raw materials replacement has returned the important class of Platinum‐group‐metal‐free electrocatalysts (PGM‐free), based on C, N, and non‐noble transition metals. PGM‐free are employed in Fuel Cells, Zinc‐Air batteries, and Electrolyzers to catalyze important energy‐related reactions. They are usually synthesized following a chemical route based on mixing, pyrolyzing, and postprocessing of specific N‐ and transition metal‐containing compounds into conductive C structures, leading to a high content of byproducts. Herein, for the first time, a new approach for PGM‐free synthesis is investigated, based on nitrogen implantation via ion beam produced with a Kaufman apparatus, and iron evaporation inside a clean chamber. The performed investigation, based on a model sp 2 carbonaceous material (vertically aligned carbon nanotubes), showed similarities to the chemical route in terms of surface functionalization with the possibility to maximize the pyridinic N content, paving the way for the first time to the synthesis of nitrogen‐compound‐free nanoelectrocatalysts.