Barrio, Jesus

Brett, Dan

Jervis, Rhodri

Li, Alain

Pedersen, Angus

Sarma, Saurav

Stephens, Ifan

Titirici, Maria-Magdalena

English

UCL Discovery

Atomic Fe in N-doped Carbon for O2 reduction: How to Achieve High Fe Loading? Angus Pedersen a,  b, Jesus Barrio a,  b, Alain Li b, Rhodri Jervis c, Dan Brett c, Saurav Sarma b, Ifan Stephens a, Maria-Magdalena Titirici b a Department of Materials Imperial College London, South Kensington, Londres SW7 2AZ, Reino Unido, United Kingdom b Department of Chemical Engineering Imperial College London, South Kensington, Londres SW7 2AZ, Reino Unido, United Kingdom c Chemical Engineering, University College London, Torrington Place, London, WC1E 7JE, United Kingdom nanoGe Fall Meeting Proceedings of Materials for Sustainable Development Conference (MAT-SUS) (NFM22) #SusEnergy - Sustainable materials for energy storage and conversion Barcelona, Spain, 2022 October 24th - 28th Organizers: Tim-Patrick Fellinger and Magda Titirici Contributed talk, Angus Pedersen, presentation 157 DOI: https://doi.org/10.29363/nanoge.nfm.2022.157 Publication date: 11th July 2022  Low temperature proton exchange membrane fuel cells powered by green hydrogen provide a means to sustainable energy production for stationary and transport applications, such as back-up power and fuel cell vehicles, respectively. Their widespread commercialisation is limited by the cost of the platinum catalyst at the cathode, where oxygen reduction occurs. Atomic FeNx sites within carbon offer a cheap and sustainable alternative, exhibiting the most promising non-precious metal activity for oxygen reduction. However, atomic Fe loading typically cannot exceed >2 wt.% without unstable and inactive FeC and Fe0 formation due to high pyrolysis temperatures (700-1000oC) required during synthesis of the conductive catalyst support. Recent progress has identified the successful use of a decoupled two-step procedure whereby Fe is incorporated at low temperature, following the high temperature pyrolysis, which has enabled >2 wt.% Fe.[1–3]  In our work, we adapt a Zn active site imprinting and subsequent low temperature (170oC) Fe (trans-)metalation process,[1] instead using a zeolitic imidazolate framework-8 precursor to yield Fe >5 wt.% (ICP-MS) with oxygen reduction active FeNx sites. The ex-situ atomic nature of the FeNx active site is elucidated by aberration corrected high-angle annular dark field scanning transmission electron microscopy, x-ray absorption spectroscopy, and electron paramagnetic resonance. The high Fe loading also enables novel characterisation by time-of-flight secondary ion mass spectrometry. References: [1] [1] Menga, D.; Ruiz-Zepeda, F.; Moriau, L.; Šala, M.; Wagner, F.; Koyutürk, B.; Bele, M.; Petek, U.; Hodnik, N.; Gaberšček, M.; Fellinger, T. P. Active-Site Imprinting: Preparation of Fe–N–C Catalysts from Zinc Ion–Templated Ionothermal Nitrogen-Doped Carbons. Adv. Energy Mater. 2019, 9, 1902412 [2] [2] Menga, D.; Low, J. L.; Li, Y.-S.; Arčon, I.; Koyutürk, B.; Wagner, F.; Ruiz-Zepeda, F.; Gaberšček, M.; Paulus, B.; Fellinger, T.-P. Resolving the Dilemma of Fe–N–C Catalysts by the Selective Synthesis of Tetrapyrrolic Active Sites via an Imprinting Strategy. J. Am. Chem. Soc. 2021, 143, 18010–18019 [3] [3] Mehmood, A.; Gong, M.; Jaouen, F.; Roy, A.; Zitolo, A.; Khan, A.; Sougrati, M.; Primbs, M.; Bonastre, A. M.; Fongalland, D.; Drazic, G.; Strasser, P.; Kucernak, A. High Loading of Single Atomic Iron Sites in Fe–NC Oxygen Reduction Catalysts for Proton Exchange Membrane Fuel Cells. Nat. Catal. 2022, 5, 311–323 Acknowledgements: A.P. thanks the EPSRC Centre for Doctoral Training in the Advanced Characterisation of Materials (grant number EP/L015277/1). I.E.L.S. and J.B. gratefully acknowledge the Engineering and Physical Sciences Research Council (EP/M0138/1), the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 866402) and the National Research Council Canada through the Materials for Clean Fuels Challenge Program. A.L. thanks the EU for the Marie Curie Research Fellowship (892614) through the project HAEMOGLOBIN.  

Atomic Fe in N-doped Carbon for O2 reduction: How to Achieve High Fe Loading?

https://discovery.ucl.ac.uk/10168953/2/Jervis_angus%20conference%20proceeding.pdf

Atomic Fe in N-doped Carbon for O2 reduction: How to Achieve High Fe Loading?

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