Electrocatalysis on model surfaces in a nutshell: from activity to material stability

ABSTRACT

Understanding catalytic reaction mechanisms and the (de)activation processes limiting their lifetime is crucial for developing more active and durable electrocatalysts. Single-crystal electrode surfaces play a key role since they are atomically precise and enable direct comparison with theoretical studies at the same surfaces.

During the first part of this talk, I will analyze the effect of surface charge and water structure on the oxygen reduction reaction (ORR) activity using Pt single crystal electrodes.¹ The application of shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) allowed the identification of the OOH* intermediate as a bifurcation point in the ORR mechanism.² The second part will address restructuring and dissolution processes of noble metal well-defined surfaces by combining on-line ICP-MS dissolution measurements with surface science techniques such as electrochemical STM and operando surface X-ray diffraction (SXRD).³

I will then introduce novel methods in electrochemistry with model systems. A newly developed D₂O purification approach was applied to study kinetic isotope effects (KIE) on the alkaline hydrogen evolution and oxidation reactions (HER and HOR) on Pt surfaces, in combination with nuclear-electronic orbital DFT (NEO-DFT) calculations and laser-induced temperature jump experiments.⁴ Fundamental studies were extended to Ru and Ni oxide single crystal electrodes prepared by molecular beam epitaxy (MBE), for which their oxygen evolution reaction (OER) activity and surface changes under reaction conditions were investigated by atomic-scale STEM images and EELS elemental maps and operando SXRD.⁵ Recent technical advances in operando electrochemical TEM allow tracking structural changes of energy materials with reliable electrochemistry,⁶ such as Cu nanocubes during CO₂ reduction.⁷

The research presented in this talk highlights the importance of understanding the reaction mechanisms and restructuring and dissolution processes at the nanoscale to provide a solid fundamental knowledge for the rational design of new electrocatalysts.⁸

References:

1. Briega-Martos, V.; Herrero, E. & Feliu, J. M. Electrochim. Acta 241, 497–509 (2017).

2. Dong, J.-C.; Zhang, X.-G.; Briega-Martos, V.; Feliu, J. M.; Li, J.-F. et al. Nat. Energy 4, 60–67 (2019).

3. (a) Briega-Martos, V., Fuchs, T., Drnec, J., Magnussen, O. M. & Cherevko, S. ChemElectroChem 11, e202300554 (2024). (b) Fuchs, T.; Briega-Martos, V.; Cherevko, S.; Magnussen, O. M. et al. Angew. Chem. Int Ed. 62, e202304293 (2023). (c) Ngoipala, A.; Schott, C. ; Briega-Martos, V.; Qamar, M. ^†; Cherevko, S.; Vandichel, M.; Gubanova, E. et al. Adv. Mater. 37, 2410951 (2025).

4. Briega-Martos, V.; Li, W.; Smith, L.; Hammes-Schiffer, S.; Yang, Y. et al. In preparation.

5. Huu, J.; Briega-Martos, V.; Yang, Y. et al. In preparation.

6. Kim, S.; Briega-Martos, V.; Yang, Y. et al. J. Am. Chem. Soc. 147, 23654–23671 (2025).

7. Yang, Y.; ...; Briega-Martos, V.; Mavrikakis, M.; Yang, P. et al. Nat. Catal. 8, 579–594 (2025).

8. Briega-Martos, V., Guzman-Soriano, R., Jiang, J. & Yang, Y. Nat. Catal. 8, 863–866 (2025).

BIO

Dr. Valentín Briega-Martos is currently a postdoctoral researcher at the Yang operando Electrochemistry group led by Asst. Prof. Yao Yang in the Chemistry and Chemical Biology Department at Cornell University (USA). He started his academic career with a MSc in Electrochemistry at the University of Alicante in Spain in 2014 and received his PhD in Electrochemistry at the same university in 2019. His research focused on fundamental electrochemistry and electrocatalysis with platinum single crystal electrodes directed by Prof. Enrique Herrero and Prof. Juan M. Feliu. During his PhD studies he stayed abroad in the Netherlands in 2016 at Leiden University under the supervision of Prof. Marc Koper, and in USA in 2018 at Caltech in the group of Prof. Manuel P. Soriaga.

He moved to Germany in 2021 as postdoctoral researcher at the Helmholtz Institute Erlangen-Nürnberg (HI-ERN) under the supervision of Dr. Serhiy Cherevko and Prof. Karl Mayrhofer and investigated the stability and dissolution processes of well-defined surfaces and materials for electrochemical energy conversion. In 2024 he moved to Cornell University, where he works on deepening the understanding of proton-coupled electron transfer (PCET) processes using single crystal electrodes and on the development of operando electrochemical methods including scanning transmission electron microscopy (STEM) and synchrotron-based X-ray methods. Dr. Valentín Briega-Martos published 50 peer-reviewed papers, of which he is first author of 20 and corresponding author of 4, and presented more than 20 works in national and international conferences and invited seminars.