65261 2025 eng 1 15 article Wiley-VCH GmbH 1 -- -- -- The decoupled synthesis of Fe-NC single-site electrocatalysts mediated by Lewis acids enables high active site density and utilization. However, current approaches often rely on small organic molecules and suffer from low synthesis yields due to the high Lewis acid-to-precursor ratios required to achieve highly porous carbons. Here, a porous organic polymer (POP) based on 2,4,6-Triaminopyrimidine (TAP) is utilized as a carbon-nitrogen-based scaffold for the synthesis of Fe─NC electrocatalysts. By tuning the amounts of MgCl2 ·6H2O used both as porogen and active site templating agent, synthetic yields exceeding 45% are achieved, a significant improvement compared to the 6% yield from the molecular analogue and the highest reported forMg2+ templated systems. Subsequent low-temperature exchange with Fe leads to atomically dispersed FeNx, minimizing Fe aggregation. The resulting materials exhibit high specific surface areas (>1000 m2 g−1) with micro-, meso-, and macropores, which promote mass transport and active site accessibility. Compared to Fe─NC synthesized via direct pyrolysis of Fe-coordinated POP, the decoupled method enables significantly higher catalytic activity in both alkaline and acidic media, and delivers 1 A cm−2 at 0.687 ± 0.004 VRHE in an alkaline gas diffusion electrode, highlighting its potential for practical oxygen reduction devices. Advanced Functional Materials 10.1002/adfm.202518944 urn:nbn:de:kobv:b43-652618 1616-3028 publish 23.03.2026 Creative Commons - CC BY - Namensnennung 4.0 International Eliot Petitdemange Jinjie Zhu Angus Pedersen Joseph Parker Esmael Balaghi Shaohua Li Silvia Favero José Ignacio Martínez Sarah Haigh Maria-Magdalena Titirici Anna Fischer Jesús Barrio eng uncontrolled Porous Organic Polymers eng uncontrolled Single Atom eng uncontrolled Oxygen reduction Angewandte Physik 3 Gefahrgutumschließungen; Energiespeicher Energie Elektrische Energiespeicher und -umwandlung Verlagsliteratur Datei für die Öffentlichkeit verfügbar ("Open Access") Wissenschaftliche Artikel der BAM 3.6 Elektrochemische Energiematerialien Bundesanstalt für Materialforschung und -prüfung (BAM) https://opus4.kobv.de/opus4-bam/files/65261/High Yield Synthesis of FeNC Electrocatalysts Using Mg Templating.pdf