This study presents an effective plasma treatment method for doping technical carbon by nitrogen- and sulfur-containing functional groups. Nitrogen incorporation shifted the oxygen reduction reaction onset potential by 0.25 V and increased the limiting current by 1 mA cm⁻², while sulfuration showed a more pronounced effect, with a 0.31 V shift in onset potential and an increase in the limiting current to 6.23 mA cm⁻². These enhancements are attributed to the formation of additional active sites and improved surface properties. The proposed plasma-based approach is simple, scalable, and environmentally friendly, minimizing the use of hazardous reagents and eliminating the need for multistep processes. This method demonstrates the potential for industrial applications using commercially available raw materials such as technical carbon and to be extended to other carbon-based materials.

The oxygen reduction reaction (ORR) plays a central role in energy conversion and storage technologies. A promising alternative to precious metal catalysts are non-precious metal doped carbons. Considerable efforts have been devoted to cobalt-doped carbonized polyacrylonitrile catalysts, but the optimization of their catalytic performance remains a key challenge. We have proposed a multifunctional active metal source strategy based on the cobalt complex with the ligand containing pyridine and azo-fragments. This complex simultaneously provides the nitrogenous environment for the Co atoms and acts as a blowing agent due to N₂ extrusion, thus increasing the surface area and porosity of the material. This strategy provided the catalysts with a high surface area and pore volume, combined with the greater fraction of Co-N clusters, and a lesser amount and smaller size of Co metal particles compared to conventionally prepared catalysts, resulting in improved catalytic performance. In addition to strict 4-electron ORR kinetics and 383 mV overpotential, the novel catalysts exhibit limiting current values close to the Pt/C benchmark and greatly overcome the Pt in methanol tolerance. These results demonstrate the critical role of metal source structure and carbonization parameters in tailoring the structural and electrochemical properties of the catalysts.