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Contributed Speaker

Assoc. Prof. Gianlorenzo Bussetti

Department of Physics, Politecnico di Milano, Italy

Sulphate adsorption mechanism on stepped Cu(111) surfaces – A combined EC- SPM investigation


Claudia Filoni a, Klaus Wandelt b,c, Rossella Yivlialin a, Lamberto Duò a, Franco Ciccacci a, Gianlorenzo Bussetti a
Department of Physics, Politecnico di Milano, p.za Leonardo da Vinci 32, I-20133 Milano, Italy
b Institute of Physical and Theoretical Chemistry, Bonn University, Wegeler Str. 12, 53115 Bonn, Germany
c Institute of Experimental Physics, University of Wroclaw, pl. M. Born 9, 50–204 Wroclaw, Poland


In today's scientific landscape, there is a growing interest in methods for surface preparation and the study of surface interactions with atomic or molecular adsorbates, offering valuable insights and experimental opportunities. However, despite the advancements in this field, a comprehensive understanding of nano-electrochemistry, particularly the influence of nanoscale structures and associated processes, remains elusive.
In this presentation, we delve into the intricate relationship between sulfate anion adsorption and nanostructures, specifically the presence of steps, on vicinal Cu(111) surfaces. Previous electrochemical scanning tunneling microscopy (EC-STM) studies on flat Cu(111) surfaces have revealed that sulfate adsorption triggers the formation of a distinct Moiré-superstructure, accompanied by the emergence of small copper islands. Similarly, on vicinal Cu(111) surfaces, the same Moiré pattern emerges through distinct growth mechanisms.
When the width of the terraces is considerably smaller than the structural Moiré-unit, the terraces widen with a concurrent movement of step edges, yet no island formation occurs. Conversely, when terraces exceed the Moiré-unit width, islands form on the terraces, mirroring observations on flat Cu(111) surfaces. Consequently, the stability of vicinal copper surfaces against sulfate anion electrochemical "attacks" hinges on step density, determined by the vicinal angle.
This investigation sheds light on the intricate dynamics between surface morphology and sulfate anion adsorption, offering valuable insights into the role of nanostructures in electrochemical processes.

 

REFERENCE:
C. Filoni, K. Wandelt, L. Marfori, M. Leone, L. Duò, F. Ciccacci, G. Bussetti, Applied Surface Science 2023, 15, 155542. https://doi.org/10.1016/j .apsusc.2022.155542