Chapter 4
Changes in Surface Stress Associated
with Underpotential Deposition
and Surface Alloying
Abstract Surface stress varies during underpotential deposition (UPD) of metal
atoms on foreign metal electrodes in electrolyte solutions containing the corresponding metallic cations. The definition of UPD, the relationship between UPD and
work function, and the equilibrium potential of UPD are explained to understand the
UPD phenomena. The typical results of the changes in surface stress induced by the
formation and structural changes of various UPD layers on a (111)-textured Au thinfilm electrode are exemplified, and the main UPD factors influencing the changes
in surface stress are discussed. As a result, the bonding of UPD atom with substrate
atom and the lattice mismatch between UPD and substrate atoms are listed as important factors influencing the changes in surface stress. Surface alloying/dealloying
processes are often involved in structural changes of UPD layers. The changes in
surface stress due to surface alloying are also discussed from the energetics viewpoint
of UPD layers.
Keywords Surface stress · Underpotential deposition (UPD) · Work function ·
Structure of UPD layer · Surface alloying
4.1 Introduction
Underpotential deposition (UPD) of metal atoms (e.g., Pb, Bi, and Cu) on foreign
noble metal electrodes such as Au, Pt, and Pd in electrolyte solutions containing the
corresponding metallic cations has been extensively investigated since the electrocatalytic activities of the noble metal electrodes for the electrochemical reactions
such as oxygen reduction, hydrogen evolution, or oxidation of organic compounds
are often enhanced by the UPD treatments of the electrode surfaces [1, 2]. The UPD
potential window in which the UPD proceeds is directly related to the difference
in work function between the UPD metal and the substrate metal. The equilibrium
potential of the UPD depends on the surface coverage of the UPD metal atom and
the activity of the corresponding metallic cations in solution.
The changes in surface stress during various UPD processes on the noble metal
electrodes can be measured by using a cantilever bending method. In addition, various
in situ surface analytical tools with an atomic resolution have been recently developed
© Springer Nature Singapore Pte Ltd. 2020
M. Seo, Electro-Chemo-Mechanical Properties of Solid Electrode Surfaces,
https://doi.org/10.1007/978-981-15-7277-7_4
103
Changes in Surface Stress Associated
with Underpotential Deposition
and Surface Alloying
Abstract Surface stress varies during underpotential deposition (UPD) of metal
atoms on foreign metal electrodes in electrolyte solutions containing the corresponding metallic cations. The definition of UPD, the relationship between UPD and
work function, and the equilibrium potential of UPD are explained to understand the
UPD phenomena. The typical results of the changes in surface stress induced by the
formation and structural changes of various UPD layers on a (111)-textured Au thinfilm electrode are exemplified, and the main UPD factors influencing the changes
in surface stress are discussed. As a result, the bonding of UPD atom with substrate
atom and the lattice mismatch between UPD and substrate atoms are listed as important factors influencing the changes in surface stress. Surface alloying/dealloying
processes are often involved in structural changes of UPD layers. The changes in
surface stress due to surface alloying are also discussed from the energetics viewpoint
of UPD layers.
Keywords Surface stress · Underpotential deposition (UPD) · Work function ·
Structure of UPD layer · Surface alloying
4.1 Introduction
Underpotential deposition (UPD) of metal atoms (e.g., Pb, Bi, and Cu) on foreign
noble metal electrodes such as Au, Pt, and Pd in electrolyte solutions containing the
corresponding metallic cations has been extensively investigated since the electrocatalytic activities of the noble metal electrodes for the electrochemical reactions
such as oxygen reduction, hydrogen evolution, or oxidation of organic compounds
are often enhanced by the UPD treatments of the electrode surfaces [1, 2]. The UPD
potential window in which the UPD proceeds is directly related to the difference
in work function between the UPD metal and the substrate metal. The equilibrium
potential of the UPD depends on the surface coverage of the UPD metal atom and
the activity of the corresponding metallic cations in solution.
The changes in surface stress during various UPD processes on the noble metal
electrodes can be measured by using a cantilever bending method. In addition, various
in situ surface analytical tools with an atomic resolution have been recently developed
© Springer Nature Singapore Pte Ltd. 2020
M. Seo, Electro-Chemo-Mechanical Properties of Solid Electrode Surfaces,
https://doi.org/10.1007/978-981-15-7277-7_4
103