Designing Co–N/C Cathode Catalysts with Dense Atomic Cobalt Sites for Enhanced PEMFC Performance

64427 2025 eng 1 11 article Wiley VHC-Verlag 1 -- -- -- Designing Co–N/C Cathode Catalysts with Dense Atomic Cobalt Sites for Enhanced PEMFC Performance Metal-nitrogen/carbon (M-N/C) catalysts, particularly those incorporating Fe,Co, or Mn, are among the most promising non-platinum group catalysts forthe acidic oxygen reduction reaction (ORR) in fuel cells. This study reports aCo-N/C catalyst featuring high (3 wt%) cobalt content exclusively present asatomic sites. Extended X-ray absorption ﬁne structure analysis conﬁrms atetrapyridinic Co-N4 coordination environment in the optimized (3.0)Co-N/C𝚫catalyst. The high cobalt loading leads to a signiﬁcant density ofelectrochemically accessible active sites, 3.58 × 10 19 sites g−1 , quantiﬁed viathe nitrite stripping method. The catalyst demonstrates excellent ORR activityin a rotating ring-disk electrode setup, achieving a half-wave potential (E 1/2 ) of0.76 V at a low loading of 0.2 mg cm−2 and a mass activity of 3.5 A g−1 at 0.80VRHE . Single-cell hydrogen-oxygen PEMFC tests achieve a peak power densityexceeding 1.3 W cm−2 (iR-corrected). Under hydrogen-air condition, thecatalyst delivers 0.54 A cm−2 at 0.60 V (0.39 W cm−2 ). Despite the intrinsicallyhigher turnover frequency of Fe-based sites, the optimized(3.0)Co-N/C𝚫 catalyst achieves similar fuel cell performance to that of Fe-N/C,highlighting the critical role of site density in overall activity. Advanced Science 10.1002/advs.202516060 urn:nbn:de:kobv:b43-644276 2198-3844 publish 27.10.2025 Creative Commons - CC BY - Namensnennung 4.0 International Mengjun Gong Asad Mehmood Ana de Oliveira Guilherme Buzanich Tim-Patrick Fellinger Colleen Jackson Junyi Cui Goran Drazic Anthony Kucernak eng uncontrolled Fuel cells eng uncontrolled Single atom catalysts eng uncontrolled Oxygen reduction reaction eng uncontrolled Non-precious catalysts 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/64427/Gong et al- Designing Co N C Cathode Catalysts with Dense Atomic Cobalt Sites for Enhanced PEMFC.pdf