Dr. Anna Mechler - Electrocatalysis
|B.Sc. (Applied Science)||University Wuppertal, Germany (2005-2008)|
|M.Sc. (Materials Science) ||University Osnabrück, Germany (2008-2010)|
|Promotion||MPI für Eisenforschung, IMPRS SurMat / Ruhr-University Bochum, Germany (2011-2014)|
|Postdoc||Université Montpellier, France (2014-2015)|
|Postdoc||MPI CEC, Heterogeneous Reactions (2016)|
|Group Leader||MPI CEC (since 2017)|
Download: Publikationsliste (.pdf)
- Spanos, I., Tesch, M.F., Yu, M., Tüysüz, H., Zhang, J., Feng, X., Müllen, K., Schlögl, R., Mechler, A.K. (2019). A facile protocol for alkaline electrolyte purification and its influence on a Ni-Co oxide catalyst for the oxygen evolution reaction ACS Catalysis 9, 8165-8170. https://doi.org/10.1021/acscatal.9b01940
- Lin, Y.; Lu, Q.; Song, F.; Yu, L.; Mechler, A.; Schlögl, R.; Heumann, S. (2019) Oxygen Evolution Reaction at Carboon Edge Sites: Activity Evolution and Structure-Function Relationships Clarified by Polycyclic Aromatic Hydrocarbons. Angewandte Chemie https://doi.org/10.1002/anie.201902884, https://doi.org/10.1002/ange.201902884
- Mechler, A.K.; Sahraie, N.R.; Armel, V.; Zitolo, A.; Sougrati, M.T.; Schwämmlein, J.N.; Jones, D.J.; Jaouen, F. (2018). Stabilization of Iron-Based Fuel Cell Catalysts by Non-Catalytic Platinum J. Electrochem. Soc. 165 (13), F1084-F1091. https://doi.org/10.1149/2.0721813jes
- C.H. Choi, W.S. Choi, O. Kasian, A.K. Mechler, M.T. Sougrati, K. Strickland, Q. Jia, S. Mukerjee, K.J.J. Mayrhofer, F. Jaouen, Unraveling the Nature of Sites Active toward Hydrogen Peroxide Reduction in Fe-N-C Catalysts, Angewandte Chemie International Edition 56 (2017) 8809-881.
- M.T. Sougrati, V. Goellner, A.K. Schuppert, L. Stievano, F. Jaouen, Probing active sites in iron-based catalysts for oxygen electro-reduction: A temperature-dependent 57Fe Mössbauer spectroscopy study, Catalysis Today. 262 (2016) 110–120.
- C.H. Choi, C. Baldizzone, G. Polymeros, E. Pizzutilo, O. Kasian, A.K. Schuppert, N. Ranjbar Sahraie, M.-T. Sougrati, K.J.J. Mayrhofer, F. Jaouen, Minimizing Operando Demetallation of Fe-N-C Electrocatalysts in Acidic Medium, ACS Catalysis. 6 (2016) 3136–3146.
- T. Öhlund, A.K. Schuppert, M. Hummelgård, J. Bäckström, H.-E. Nilsson, H. Olin, Inkjet Fabrication of Copper Patterns for Flexible Electronics: Using Paper with Active Precoatings, ACS Applied Materials & Interfaces. 7 (2015) 18273–18282.
- T. Öhlund, A.K. Schuppert, B. Andres, H. Andersson, S. Forsberg, W. Schmidt, H.-E. Nilsson, M. Andersson, R. Zhang, H. Olin, Assisted sintering of silver nanoparticle inkjet ink on paper with active coatings, RSC Adv. 5 (2015) 64841-64849.
- C.H. Choi, C. Baldizzone, J.-P. Grote, A.K. Schuppert, F. Jaouen, K.J.J. Mayrhofer, Stability of Fe-N-C Catalysts in Acidic Medium Studied by Operando Spectroscopy, Angewandte Chemie International Edition. 54 (2015) 12753–12757.
- A.K. Schuppert, A. Savan, A. Ludwig, K.J.J. Mayrhofer, Potential-resolved dissolution of Pt-Cu: A thin-film material library study, Electrochimica Acta. 144 (2014) 332–340.
- V. Goellner, C. Baldizzone, A.K. Schuppert, M.T. Sougrati, K.J.J. Mayrhofer, F. Jaouen, Degradation of Fe/N/C catalysts upon high polarization in acid medium, Physical Chemistry Chemical Physics. 16 (2014) 18454.
- C. Baldizzone, S. Mezzavilla, H.W.P. Carvalho, J.C. Meier, A.K. Schuppert, M. Heggen, C. Galeano, J.-D. Grunwaldt, F. Schüth, K.J.J. Mayrhofer, Confined-Space Alloying of Nanoparticles for the Synthesis of Efficient PtNi Fuel-Cell Catalysts, Angewandte Chemie International Edition. 53 (2014) 14250–14254.
- A.K. Schuppert, Combinatorial screening of fuel cell catalysts for the oxygen reduction reaction. Ruhr-Universität Bochum, Germany (2014). www-brs.ub.rub.de/netahtml/HSS/Diss/SchuppertAnnaKatharina/
- A.K. Schuppert, A.A. Topalov, A. Savan, A. Ludwig, K.J.J. Mayrhofer, Composition-Dependent Oxygen Reduction Activity and Stability of Pt-Cu Thin Films, ChemElectroChem. 1 (2013) 358–361.
- A.K. Schuppert, A.A. Topalov, A. Savan, A. Ludwig, K.J.J. Mayrhofer, Pt-Cu Alloys as Catalysts for the Oxygen Reduction Reaction - A Thin-Film Study of Activity and Stability, ECS Transactions. 58 (2013) 587–592.
- A.K. Schuppert, A.A. Topalov, I. Katsounaros, S.O. Klemm, K.J.J. Mayrhofer, A Scanning Flow Cell System for Fully Automated Screening of Electrocatalyst Materials, J. Electrochem. Soc. 159 (2012) F670–F675.
- S.O. Klemm, A. Karschin, A.K. Schuppert, A.A. Topalov, A.M. Mingers, I. Katsounaros, K.J.J. Mayrhofer, Time and potential resolved dissolution analysis of rhodium using a microelectrochemical flow cell coupled to an ICP-MS, J. Electroanal. Chem. 677–680 (2012) 50–55.
- A. Schuppert, M. Thielen, I. Reinhold, W.A. Schmidt, Ink Jet Printing of Conductive Silver Tracks from Nanoparticle Inks on Mesoporous Substrates. NIP27: International Conference on Digital Printing Technologies and Digital Fabrication 2011 437–440 (2011).
- A. Schuppert, F. Jaouen, D. Jones, Catalyseur hybride de type P/Métal-N-C. Application France No. 15/58452, 11.09.2015
In our group we investigate electrocatalytic active materials that facilitate the conversion of electrical energy to chemical energy and vice versa. For the storage of excess electrical energy, as for example from sustainable energy sources, water electrolysis is a feasible technique to generate hydrogen (and oxygen), where the energy is stored in chemical bonds. Here we focus on the rate-limiting oxygen evolution reaction in alkaline media. The advantage of alkaline media is the higher stability of non-noble materials, as for instance functionalized carbon materials as produced by the "Carbon Synthesis and Application" group (Dr. Saskia Heumann).
On the other hand we study catalysts for the reverse reaction, i.e. the oxygen reduction reaction. This reaction takes place on the cathode of a fuel cell, therefore enabling the re-conversion to electrical energy. Also here we use materials based on carbon, doped with iron or other transition metals to boost their activity. In addition hybrid materials of the combination of these non-precious metal catalysts with low amounts of precious metals are investigated to find possible synergies of these different material classes.
For a proper analysis we develop new experimental techniques, including for example an electrochemical flow cell coupled to an inductively coupled plasma optical emission spectrometer (ICP-OES) to characterize the stability of various catalyst materials. This cell also enables the implementation of further in situ techniques to improve our knowledge of material property changes during the electrochemical reaction.
For standard electrochemical testing we use several complementary setups that help us to address different aspects of electrocatalytic material properties.
1. Rotating (ring) disc electrodes (R(R)DE)
For rotating disc electrode studies powder catalysts are dispersed in an ink and then drop-casted onto a disc-shaped support. These supporting materials can vary from glassy carbon, gold or titanium. By the in-house fabrication of electrode tips we can produce a high variety of tips that are in some cases even exchangeable between different setups. Due to the small dimensions of the tips they are additionally suitable for post-mortem characterization as for example by optical microscopy, SEM, or IR/Raman.
From the MANGAN Project we are equipped with a RDE setup that is identical to that installed at 13 collaboration partners. The electrochemical cell is made out of peek connected to a thermostat, so that also measurements at controlled and elevated temperatures are possible. The rotator and potentiostat are from AutoLab and are managed via the Nova software environment, also equipped with an electrochemical impedance module. In this setup especially measurements for the MANGAN project according to the predefined standard procedure are performed, but the standardized format also facilitates studies on the influence of several experimental parameters.
Additional we have two R(R)DE test stations with rotators by PINE instruments. The electrochemical tests are run with a Biologic VMP 3 potentiostat. These setups allow the use of ring-disc-electrodes for the detection of reaction products like oxygen or hydrogen peroxide on the ring. They are also typically run under a controlled gas atmosphere and due to the closed cell-design can even be operated with e.g. H2 and CO, as for example necessary for CO-stripping experiments.
2. Electrochemical Flow Cell + ICP-OES
With this setup, financed by MAXNET Energy, we can comprehensively characterize the catalyst performance. By combining an electrochemical ﬂow cell (EFC) with a Clark electrochemical oxygen sensor and inductively coupled plasma−optical emission spectrometry (ICP-OES) we cannot only address the electrocatalytic activity and stability, but also monitor metal ions in the electrolyte as well as oxygen content. This allows for a quantitative transient analysis of catalyst corrosion products such as dissolved metal species during an electrochemical stress test as well as to monitor changes of the electrolyte composition (for example of impurities). The oxygen sensor allows accessing the faradaic efficiency and its changes by catalyst corrosion.