@article{nokey,

title = {Scanning impedance microscopy under oxygen reduction reaction conditions. Proof of the concept},

author = {C Schott and L Hofbauer and E Gubanova and P Schneider and A S Bandarenka},

url = {https://www.sciencedirect.com/science/article/pii/S0013468624017699},

doi = {https://doi.org/10.1016/j.electacta.2024.145533},

issn = {0013-4686},

year  = {2025},

date = {2025-02-10},

journal = {Electrochimica Acta},

volume = {513},

pages = {145533},

abstract = {In this study, we demonstrate that localized electrochemical impedance spectroscopy (LEIS) can successfully probe the solid-liquid interface of a model gold surface in low-concentrated aqueous electrolytes. The approach utilizes scanning electrochemical microscopy (SECM) under potential control of the sample, marking a notable improvement over previous SECM-based LEIS studies, which were conducted under open circuit potential conditions. The accuracy of the results was validated by comparing the interfacial parameters, such as the double-layer capacitance minimum and the potential of zero charge, with the results obtained from conventional global measurements. Additionally, local kinetic parameters for the oxygen reduction reaction (ORR) were examined via LEIS by fitting the acquired impedance spectra to a simplified, physical equivalent circuit model. Gold was chosen as a model surface for the ORR with its well-defined ORR potential region due to the absence of hydrogen adsorption and overlapping OH⁻ adsorption. The local kinetic parameter determined from the LEIS experiments corresponds to the apparent rate coefficient (kapp) of the ORR, reflecting the average kapp of individual active sites within the probed area. The dependence of kapp on the ORR overpotential aligns well with the kinetics of the 2-electron reduction of O2 taking place at the gold sample. This proof-of-concept study demonstrates that SECM-based LEIS serves as a powerful tool for the advanced characterization of complex electrochemical interfaces for future experiments, especially those with heterogeneities or different structures/materials.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Stability of the Au/electrolyte interface during hydrogen evolution: A Cyclic Plasmo-Voltammetry study},

author = {M J Feil and S Leisibach and M Becherer and K Krischer},

url = {https://www.sciencedirect.com/science/article/pii/S0013468624017456},

doi = {https://doi.org/10.1016/j.electacta.2024.145509},

issn = {0013-4686},

year  = {2025},

date = {2025-02-10},

journal = {Electrochimica Acta},

volume = {513},

pages = {145509},

abstract = {Metal-electrolyte interfaces are dynamic entities, the potential and electrolyte dependent mobility of the metal atoms leading to surface restructuring with possible dissolution and degradation. In this work, we investigate the stability of the Au/aqueous electrolyte interface with in situ differential Cyclic Plasmo-Voltammetry (dCPV), augmented by ex situ atomic force microscopy and finite differential time domain simulations. We demonstrate that even the onset of hydrogen evolution is accompanied by pronounced morphological changes of the interface which are by far more prominent than those occurring during Au oxidation and reduction. Furthermore, the stability of the interface heavily depends on pH, the degradation of the electrode being considerably stronger in acidic than in neutral electrolyte. In addition, a clear hydrogen adsorption peak was observed in neutral electrolytes during the cathodic scan, which was more pronounced on a freshly prepared Au electrode than on an aged one. The measured dCPVs in acidic and neutral electrolytes can be explained consistently assuming that (1) adsorbed hydrogen is absorbed into the subsurface region of the Au electrode once HER starts; its subsequent removal as molecular hydrogen causes morphological changes; (2) in the presence of metal cations, adsorbed hydrogen is stabilized through the formation of ternary metal hydrides on the gold surface that stabilize the surface Au-H bonds and hinder further absorption of H into the subsurface region as well as the release of hydrogen into the electrolyte.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Exploring the atomic-scale dynamics of Fe3O4(001) at catalytically relevant temperatures using FastSTM},

author = {J Reich and S Kaiser and A Bourgund and M Krinninger and U Heiz and F Esch and B A J Lechner},

url = {https://www.sciencedirect.com/science/article/pii/S0039602824001857},

doi = {https://doi.org/10.1016/j.susc.2024.122634},

issn = {0039-6028},

year  = {2025},

date = {2025-02-01},

urldate = {2025-02-01},

journal = {Surface Science},

volume = {752},

pages = {122634},

abstract = {Surfaces and interfaces of functional nanoscale materials are typically highly dynamic when employed at elevated temperatures. Both, lateral surface and vertical bulk exchange diffusion processes set in, which can be relevant for applications such as heterogeneous catalysis. Time-resolved scanning tunneling microscopy (STM) is being pushed to ever faster measurement modes to follow such dynamic phenomena in situ. Here, we present FastSTM movies monitoring a range of atomic-scale dynamics of a prototypical reducible oxide catalyst support, Fe3O4(001), at elevated temperatures. Antiphase domain boundaries between two domains of the reconstructed surface exhibit local mobility from around 350 K, while Fe-rich point defects, in a stable equilibrium with the bulk, appear to diffuse in a peculiar zigzag pattern above 500 K. Finally, exploiting the diffusivity of Fe interstitials, we follow the propagation of step edges in the topmost atomic layer of the Fe3O4(001) surface in an oxygen atmosphere.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}