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In situ friction study of Ag Underpotential deposition (UPD) on Au(111) in aqueous electrolyte
Author(s) -
Park Inhee,
Baltruschat H.
Publication year - 2021
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202100130
Subject(s) - underpotential deposition , monolayer , bilayer , aqueous solution , sulfate , penetration (warfare) , adsorption , sulfuric acid , chemistry , electrochemistry , electroplating , transition metal , electrolyte , deposition (geology) , analytical chemistry (journal) , inorganic chemistry , layer (electronics) , materials science , cyclic voltammetry , electrode , membrane , catalysis , organic chemistry , paleontology , sediment , biology , biochemistry , operations research , engineering
The electrodeposition of silver on Au(111) was investigated using lateral force microscopy (LFM) in Ag + containing sulfuric acid. Friction force images show that adsorbed sulfate forms3 × 7 R 19 . 1 ∘structure ( θ s u l f a t e= 0 . 2 )on Au(111) prior to Ag underpotential deposition (UPD) and ( 3 × 3 R 30 ∘) structure ( θ s u l f a t e = 0 . 33 ) on a complete monolayer or bilayer of Ag. Variation of friction with normal load shows a non‐monotonous dependence, which is caused by increasing penetration of the tip into the sulfate adlayer. In addition, the friction force is influenced by the varying coverage and mobility of Ag atoms on the surface. Before Ag coverage reaches the critical value, the deposited silver atoms may be mobile enough to be dragged by the movement of AFM tip. Possible penetration of the tip into the UPD layer at very high loads is discussed as a model for self‐healing wear. However, when the coverage of Ag is close to 1, the deposited Ag atoms are tight enough to resist the influence of the AFM tip and the tip penetrates only into the sulfate adlayer.