
Liquid Phase Electron and X-ray Microscopy
Our research aims to derive critical structure-property relationships that control the performance of nanoscale electrocatalysts through in situ characterization with electron microscopy and its associated spectroscopic techniques. In particular, we are interested in operando studies where the imaging of catalysts in liquid environments is coupled with concurrent measurements of their reaction kinetics.
This approach will allow us to directly interrogate the structure and composition of these catalysts under reaction conditions and generate insights that can be used to inform the rational design of these nanomaterials. Other areas of interest of the group include: (1) automated image processing of high frame count electron microscope image sequences, (2) advanced image analysis of low quality images acquired at low electron fluences, and (3) the development of multi-modal approaches towards catalyst characterization using methods complementary to electron microscopy, such as transmission X-ray microscopy measurements at the synchrotron facilities.

Group Members
Name
Room
Phone
Email
F 3.03
- 4172
F 1.02-I
- 4218
F 3.07
- 4124
F 3.06
- 5408
F 1.02a-II
- 4269
F 1.02a-I
- 4142
FHI Electron Microscopy Facility
Name
Room
Phone
Email
F 2.03
- 4582 / 4638
F 3.03 / F K.07
- 4233 / 4515
Recent Publications
peer-reviewed
2025
A. Yoon, L. Bai, F. Yang, F. Franco, C. Zhan, M. Rüscher, J. Timoshenko, , , H. Jeon, M.C.O. Monteiro, S.W. Chee and B. Roldan Cuenya: Revealing catalyst restructuring and composition during nitrate electroreduction through correlated operando microscopy and spectroscopy. Nature Materials, in press.
2024
M.L. De Marco, , , , and S.W. Chee: Understanding the Growth of Electrodeposited PtNi Nanoparticle Films Using Correlated In Situ Liquid Cell Transmission Electron Microscopy and Synchrotron Radiation. , , , Nano Letters 24 (40), 12361–12367 (2024).
S.W. Chee and : Operando Liquid-cell Transmission Electron Microscope Sample Holder with Bulk Reference and Counter Electrodes for Electrocatalysis Applications. , Microscopy and Microanalysis 30 (Suppl 1), 1213–1214 (2024).
L. Bai, F. Franco, J. Timoshenko, C. Rettenmaier, F. Scholten, H. Jeon, A. Yoon, M. Rüscher, A. Herzog, F. Haase, S. Kühl, S.W. Chee, A. Bergmann and B. Roldan Cuenya: Electrocatalytic Nitrate and Nitrite Reduction toward Ammonia using Cu2O Nanocubes: Active Species and Reaction Mechanisms. Journal of the American Chemical Society 146 (14), 9665–9678 (2024).
D. Kordus, S. Widrinna, J. Timoshenko, M. Lopez-Luna, C. Rettenmaier, S.W. Chee, E. Ortega, O. Karslıoğlu, S. Kühl and B. Roldan Cuenya: Enhanced Methanol Synthesis from CO2 Hydrogenation Achieved by Tuning the Cu-ZnO Interaction in ZnO/Cu2O Nanocube Catalysts Supported on ZrO2 and SiO2. Journal of the American Chemical Society 146 (12), 8677–8687 (2024).
M. Lopez Luna, F. Yang, A. Yoon, , , S.W. Chee and B. Roldan Cuenya: Revealing the Intrinsic Restructuring of Bi2O3 Nanoparticles into Bi Nanosheets during Electrochemical CO2 Reduction. , ACS Applied Materials and Interfaces 16 (9), 11552–11560 (2024).
D. Hursán, J. Timoshenko, E. Ortega, H. Jeon, M. Rüscher, A. Herzog, C. Rettenmaier, S.W. Chee, A. Martini, D. Koshy and B. Roldan Cuenya: Reversible Structural Evolution of Metal-Nitrogen-Doped Carbon Catalysts During CO2 Electroreduction: An Operando X-ray Absorption Spectroscopy Study. Advanced Materials 36 (4), 2307809 (2024).
C. Rettenmaier, A. Herzog, , M. Rüscher, H. Jeon, D. Kordus, M. Lopez-Luna, S. Kühl, U. Hejral, E. Davis, S.W. Chee, J. Timoshenko, , A. Bergmann and B. Roldan Cuenya: Operando insights into correlating CO coverage and Cu-Au alloying with the selectivity of Au NP-decorated Cu2O nanocubes during the electrocatalytic CO2 reduction. EES Catalysis 2 (1), 311–323 (2024).
2023
S.W. Chee, T. Lunkenbein, R. Schlögl and B. Roldan Cuenya: Operando Electron Microscopy of Catalysts: The Missing Cornerstone in Heterogeneous Catalysis Research? Chemical Reviews 123 (23), 13374–13418 (2023).
F. Yang, M. Lopez-Luna, F. Haase, D. Escalera Lopez, A. Yoon, M. Rüscher, C. Rettenmaier, H. Jeon, E. Ortega, J. Timoshenko, A. Bergmann, S.W. Chee and B. Roldan Cuenya: Spatially and Chemically Resolved Visualization of Fe Incorporation into NiO Octahedra during the Oxygen Evolution Reaction. Journal of the American Chemical Society 145 (39), 21465–21474 (2023).
F. Yang, M. Lopez-Luna, F. Haase, D. Escalera Lopez, A. Yoon, , , A. Bergmann, B. Roldan Cuenya and S.W. Chee: Tracking the Incorporation of Fe into NiO Electrocatalysts during Reaction with Liquid Phase Electron Microscopy and Time-Resolved Elemental Mapping. Microscopy and Microanalysis 29 (Suppl 1), 1302–1303 (2023).
D. Kordus, , M. Lopez-Luna, , J. Timoshenko, S.W. Chee, C. Rettenmaier, J. Kröhnert, S. Kühl, A. Trunschke, R. Schlögl, and B. Roldan Cuenya: Shape-Dependent CO2 Hydrogenation to Methanol over Cu2O Nanocubes Supported on ZnO. Journal of the American Chemical Society 145 (5), 3016–3030 (2023).
2022
S.W. Chee and B. Roldan Cuenya: 2022 Roadmap on Low Temperature Electrochemical CO2 Reduction: Mechanistic insight into the electrocatalytic reduction of CO2 via operando spectroscopy and microscopy methods. Journal of Physics: Energy 4 (4), 042003 (2022).
A. Yoon, J. Poon, P. Grosse, S.W. Chee and B. Roldan Cuenya: Iodide-mediated Cu catalyst restructuring during CO2 electroreduction. Journal of Materials Chemistry A 10 (26), 14041–14050 (2022).
W. Wan, , N. Berdunov, M. Lopez-Luna, S.W. Chee, , , S.K. Shaikhutdinov and B. Roldan Cuenya: Highly Stable and Reactive Platinum Single Atoms on Oxygen Plasma-Functionalized CeO2 Surfaces: Nanostructuring and Peroxo Effects. Angewandte Chemie International Edition 61 (20), e202112640 (2022).
2021
H. Jeon, J. Timoshenko, C. Rettenmaier, A. Herzog, A. Yoon, S.W. Chee, S. Oener, U. Hejral, F. Haase and B. Roldan Cuenya: Selectivity control of Cu nanocrystals in a gas-fed flow cell through CO2 pulsed electroreduction. Journal of the American Chemical Society 143 (19), 7578–7587 (2021).
M. Lopez-Luna, J. Timoshenko, D. Kordus, C. Rettenmaier, S.W. Chee, , , S.K. Shaikhutdinov and B. Roldan Cuenya: Role of the Oxide Support on the Structural and Chemical Evolution of Fe Catalysts during the Hydrogenation of CO2. ACS Catalysis 11 (10), 6175–6185 (2021).
S.W. Chee, T. Lunkenbein, R. Schlögl and B. Roldan Cuenya: In situ and operando electron microscopy in heterogeneous catalysis - insights into multi-scale chemical dynamics. Journal of Physics: Condensed Matter 33 (15), 153001 (2021).
D. Kordus, J. Timoshenko, , , A. Bergmann, S.W. Chee, S. Widrinna, O. Karslıoğlu, , M. Lopez Luna, J.Q. Zhong, , , , , , and B. Roldan Cuenya: Operando high-pressure investigation of size-controlled CuZn catalysts for the methanol synthesis reaction. , Nature Communications 12, 1435 (2021).
A. Yoon, A. Herzog, P. Grosse, , S.W. Chee and B. Roldan Cuenya: Dynamic Imaging of Nanostructures in an Electrolyte with a Scanning Electron Microscope. Microscopy and Microanalysis 27 (1), 121–128 (2021).
P. Grosse, A. Yoon, C. Rettenmaier, A. Herzog, S.W. Chee and B. Roldan Cuenya: Dynamic transformation of cubic copper catalysts during CO2 electroreduction and its impact on catalytic selectivity. Nature Communications 12, 6736 (2021).
2020
C. Rettenmaier, R. Aran Ais, J. Timoshenko, R. Rizo, H. Jeon, S. Kühl, S.W. Chee, A. Bergmann and B. Roldan Cuenya: Enhanced Formic Acid Oxidation over SnO2-decorated Pd Nanocubes. ACS Catalysis 10 (24), 14540–14551 (2020).
P. Grosse, A. Yoon, C. Rettenmaier, S.W. Chee and B. Roldan Cuenya: Growth Dynamics and Processes Governing the Stability of Electrodeposited Size-Controlled Cubic Cu Catalysts. The Journal of Physical Chemistry C 124 (49), 26908–26915 (2020).
S. Kunze, P. Grosse, , , , , J. Timoshenko, , , , S.W. Chee and B. Roldan Cuenya: Operando NRIXS and XAFS Investigation of Segregation Phenomena in Fe‐Cu and Fe‐Ag Nanoparticle Catalysts during CO2 Electroreduction. Angewandte Chemie International Edition 59 (50), 22667–22674 (2020).
R. Aran Ais, R. Rizo, P. Grosse, G. Algara-Siller, K. Dembélé, M. Plodinec, T. Lunkenbein, S.W. Chee and B. Roldan Cuenya: Imaging electrochemically synthesized Cu2O cubes and their morphological evolution under conditions relevant to CO2 electroreduction. Nature Communications 11, 3489 (2020).
2024
S.W. Chee, A. Yoon, S.-Y. Fu and B. Roldan Cuenya: Tracking Morphology and Chemical State of Electrocatalysts during Reaction through Correlated Electron Microscopy, X-ray Microscopy and X-ray Absorption Spectroscopy Experiments. In: Microscopy and Microanalysis. Cambridge University Press, New York, NY, ozae044.228 (2024).
Book Chapters
2026
J. Poon, S.W. Chee, J. Timoshenko and B. Roldan Cuenya: Operando Studies of Electrocatalysts for Energy Technology Reactions. In: Operando Methods in Catalysis and Materials Science. (Eds.): and . Willey-VCH, , 11–111 (2026).
Articles
non peer-reviewed
2021
S.W. Chee, , F. Yang, P. Grosse, J. Poon and B. Roldan Cuenya: Understanding Structure-Property Relationships in Nanoparticle Electrocatalysts through Correlated Electron Microscopies. Microscopy and Microanalysis 27 (S1), 52–53 (2021).
Talks
2025
Probing the Evolution of Electrocatalyst Structure and Chemical State During Reaction Using Correlated Electron and X-Ray Microscopy. In-situ EC-(S)TEM - Dynamics of Electrochemical Energy Materials at the Nanoscale Workshop, University of Freiburg, Freiburg, Germany (2025)
Revealing the Structural and Chemical Evolution of Electrocatalysts Using Correlated Operando Electron and X-Ray Microscopy. IMX Mini-Symposium, EPFL, Lausanne, Switzerland (2025)
Revealing the Structural and Chemical Evolution of Electrocatalysts Using Correlated Operando Electron and X-Ray Microscopy. Seminar, Nanyang Technological University, Singapore, Singapore (2025)
2024
Probing the Heterogeneity and Complexity in Electrocatalysts Under Reaction Conditions Through Operando Microscopy. 6th Joint Sino-German Workshop on Advanced and Correlative Electron Microscopy of Catalysts, Quantum Phenomena and Soft Matter, Bad Honnef, Germany (2024)
30 (Suppl. 1), ozae044.228, (2024)
Tracking Morphology and Chemical State of Electrocatalysts during Reaction through Correlated Electron Microscopy, X-ray Microscopy and X-ray Absorption Spectroscopy Experiments. Microscopy and Microanalysis
Studying Electrocatalysts During Reaction With Operando Microscopy: From Electrons to X-Rays. InCAEM Seminar, ALBA-CELLS Synchrotron Light Facility, Barcelona, Spain (2024)
Correlative Operando Electron and X-Ray Microscopy of Electrocatalysts Under Reaction Conditions. IMPRESS School on Operando and Correlative Experiments, ALBA-Synchrotron, Barcelona, Spain (2024)
Bridging the Nanoscale and the Ensemble Through Correlated Operando Electron and X-ray Microscopy Experiments. X-rays and electronic operando techniques for electrocatalysis, EcatalytiX, Strasbourg, France (2024)
Synthesizing Well-Defined Pre-catalysts for Multi-Modal Studies of Electrocatalysts Under Reaction Conditions. 2024 MRS Spring Meeting, Seattle, WA, USA (2024)
2023
Understanding Electrocatalyst Restructuring During Reaction With Electrochemical Cell Transmission Electron Microscopy. 5th Sino-German Symposium on Advanced Electron Microscopy and Instrumentation, Hong Kong, China (2023)
Operando Electron Microscopy of Electrocatalyst Transformations under CO2 Electroreduction Conditions. International Symposium on Green Transformation of Carbon Dioxide (ISGTCO2), Brisbane, Australia (2023)
Studying Electrocatalysts During Reaction With Operando Electrochemical Cell Transmission Electron Microscopy. Future of Microscopy Seminar Series, Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore (2023)
Studying Electrocatalysts During Reaction With Operando Electrochemical Cell Transmission Electron Microscopy. NEMI Day 2023, Eindhoven, The Netherlands (2023)
Liquid Phase Electron Microscopy and Spectroscopy of Electrocatalyst Transformations Under Working Conditions. Workshop on TEM Characterization Techniques Focusing on In-Situ and EELS, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, Jülich, Germany (2023)
2022
Electrocatalyst Transformations Under Reaction Conditions: Insights From Operando TEM of Well-Controlled Pre-catalysts. 2022 MRS Fall Meeting & Exhibition, Online Event (2022)
Quantitative Insights Into the Structure-Property Relationships in Electrocatalysts Using Electrochemical Cell Transmission Electron Microscopy. Gordon Conference, Liquid Phase Electron Microscopy, Ventura, CA, USA (2022)
2021
Probing the Complex Restructuring of Electrocatalysts Under Reaction Conditions Using Electrochemical Cell Transmission Electron Microscopy. Virtual Vacuum Congress 2021, Online Event (2021)
Understanding Structure-Property Relationships in Nanoparticle Electrocatalysts Through Correlated Electron Microscopies. Microscopy and Microanalysis 2021, Online Event (2021)
2020
Revealing the Dynamics of Electrocatalysts Under Reaction Conditions Using Liquid Phase Electron Microscopy. 3rd International Symposium on Advanced Microscopy and Spectroscopy, Online Event (2020)
Capturing the Dynamic Evolution of Electrocatalysts Under Reaction Conditions With Liquid Phase Electron Microscopy. Conference Electrochemistry undercover, Online Event (2020)
Investigating the Behavior of Cu-Based Catalysts During Electrochemical CO2 Reduction With Liquid Cell Electron Microscopy. Microscopy & Microanalysis 2020 Meeting, Online Event (2020)
Seeing Catalysts in Action: Opportunities and Challenges With Environmental Cell Electron Microscopy. SEEN 2020: Solutions for Environmental Nanoscopy, Lyon, France (2020)
2019
Direct Observations of Morphology Changes in Copper Nanoparticles During Electrochemical Cycling Using Liquid Cell TEM. 8th Science Day of the Max Planck-EPFL Center for Molecular Nanoscience & Technology, Lausanne, Switzerland (2019)