Description
Single atom catalysts (SACs) based on atomically dispersed transition metals in a Nitrogen-doped Carbon (M-N-C, where M = Fe, Ni, Co, Cr, Cu…) show highly promising intrinsic activity and selectivity in different electrochemical reactions, including O2 reduction and CO2 conversion.[1,2] These reactions are critical to the performance of industrially relevant hydrogen fuel cells and CO2 electrolysers. The active sites in M-N-Cs are composed of bioinspired M-N4 sites, which can be found in enzymes such as heme, and can benefit from resource efficient synthesis through 100% metal utilisation from their atomic dispersion. Controlled synthesis of M-N4 sites in M-N-Cs has remained challenging due to the high temperatures during the synthesis process, which is required to obtain sufficient electronic conductivity for electrochemical devices. The most promising M-N-C synthesis method is based on active site templating, using an unreactive metal at high temperature, such as Mg or Zn, to template the active sites and then subsequently load in the active metal.[3,4] This metal loading step can be conducted in a number of ways and has typically involved high quantities of solvents, precursors, and/or temperatures, which have large environmental impacts and limits scalability.[5] Mechanochemical methods, such as ball milling, offers an alternative sustainable, facile and scalable process for both the synthesis and also active metal loading of M-N-Cs, as well as affecting the structural properties of the M-N-C, which can improve electrochemical performance.[6]
The thesis project, based in the field of materials chemistry and electrochemistry, will explore ball milling parameters for the optimised production of SAC M-N-Cs with desirable properties for electrochemical O2 reduction and CO2 reduction. The synthesised catalysts will be characterised by XRD, TEM, XPS, ICP-MS, among others, as well their key electrochemical properties, such as mass activity, turnover frequency, and electrochemical double layer capacitance in both screening and practical electrochemical devices. Therefore, the student will gain a wide and thorough understanding on the synthesis of catalysts, characterisation methods and electrochemical testing, which will be desirable in both industry and academia.
Qualifications
Background in chemistry, materials science, chemical engineering, or related subjects. Experience in electrochemistry is desirable but not required.
Qualities
We seek a motivated team-player who is scientifically curious to join our like-minded team.
Project Related Publications
[1] A. Pedersen, A. Bagger, J. Barrio, F. Maillard, I. Stephens, M.-M. Titirici, J. Mater. Chem. A 2023, 11, 23211.
[2] S. C. Sarma, J. Barrio, A. Bagger, A. Pedersen, M. Gong, H. Luo, M. Wang, S. Favero, C. Zhao, Q. Zhang, A. Kucernak, M. Titirici, I. E. L. Stephens, Adv. Funct. Mater. 2023, 2302468.
[3] A. Mehmood, J. Pampel, G. Ali, H. Y. Ha, F. Ruiz-Zepeda, T.-P. Fellinger, Adv. Energy Mater. 2018, 8, 1701771.
[4] D. Menga, J. L. Low, Y.-S. Li, I. Arčon, B. Koyutürk, F. Wagner, F. Ruiz-Zepeda, M. Gaberšček, B. Paulus, T.-P. Fellinger, J. Am. Chem. Soc. 2021, 143, 18010.
[5] A. Pedersen, J. Pandya, G. Leonzio, A. Serov, A. Bernardi, I. Stephens, M.-M. Titirici, C. Petit, B. Chachuat, Green Chem. 2023, 25, 10458.
[6] S. Ünsal, T. J. Schmidt, J. Herranz, Electrochimica Acta 2023, 445, DOI 10.1016/j.electacta.2023.142024.
Contact
Dr. Angus Pedersen
Division 3.6 Electrochemical Energy Materials
Phone: 030-8104-4348
email: angus-nils.pedersen@bam.de
Dr. Tim-Patrick Fellinger
Division 3.6 Electrochemical Energy Materials
Phone: 030-8104-3669
email: tim-patrick.fellinger@bam.de