A Dynamic Core Modulation Strategy for Enhancing Active Sites of Polymer-Derived Carbon Electrocatalysts

Polymer-derived carbons have emerged as efficient and economical electrocatalysts for energy-related reactions such as oxygen reduction and hydrogen evolution. However, their performance often faces an inherent trade-off between porosity and electronic conductivity, necessitating precise regulation of composition and structure at the molecular level. To enhance the formation of accessible active sites, we construct a series of core@polyaniline precursors with systematically varied organic cores (a nitrogen-rich polymer (NPS), polysaccharide (GluS), and polyaniline (PANI) itself). Metals ions are introduced during the shell polymerization. The resultant core-shell precursors were then subjected to pyrolysis, where the carbon network forms with Fe-N active sites generated inside. We propose that the core polymer remotely modulates the formation of active sites in the carbon shell during pyrolysis. Through combined structural characterization and electrocatalytic evaluation, we find that the nitrogen-rich polymeric core, which undergoes pronounced volume change during pyrolysis, promotes the formation of a more graphitized, electron-conductive carbon network with a higher density of accessible Fe-N sites. In contrast, the polysaccharide core with a mild pyrolysis profile and the chemically identical PANI core lack this dynamic templating ability and do not effectively optimize the carbon structure. Through this dynamic core modulation, a Fe/Ni co-loaded catalyst was also prepared, achieving excellent bifunctional ORR/HER performance, with an ORR half-wave potential of 0.89 V (vs RHE) and an HER overpotential of 298 mV, along with good stability. This work provides a new perspective for the rational design of polymer-derived carbon electrocatalysts, shifting attention from static precursor composition to the dynamic role of the core during pyrolysis.