Electrodeposition of Ag and Pd on a reconstructed Au(1 1 1) electrode surface studied by in situ scanning tunneling microscopy

Abstract

Electrochemical deposition of Ag and potential-induced structural change of the deposited Ag layer on a 23 3  reconstructed surface of Au (111)

Towards Size‐Controlled Deposition of Palladium Nanoparticles from Polyoxometalate Precursors: An Electrochemical Scanning Tunneling Microscopy Study

“…Noticeably, at the low coverage of particles forming under the tip, we can observe a distinct preference for specific nucleation sites. As this deposition took place on a reconstructed Au(111) surface, we attribute the line order to the presence of elbow sites of the herringbone structure where nucleation is favored, as reported for UHV vapor deposited [49,50] or electrochemically deposited Pd particles on reconstructed Au(111) [27] . The preference for defect sites and steps after hydrogen preconditioning underlines a considerable mobility of the particles forming in the deposition process, in line with the observed tendency to aggregate.…”

“…This is in line with an expected epitaxial growth, as seen in most previous studies, [26,33] except for the very slow deposition in highly dilute electrolytes on the reconstructed surface by Uosaki et al, in which 3D particles up to three layers high have been found. [27] Note that different tip radii might slightly influence the observed area, but not the observed height distributions.…”

“…Electrochemical Scanning Tunneling Microscopy (EC-STM) has already proven to be a powerful method to investigate in situ, at the local scale and under potential control the deposition of small Pd particles from simple salt solutions and their properties. [24][25][26][27][28][29] As supports, both reconstructed Au(111)-(22 × p 3) and unreconstructed Au(111)-(1 × 1) surfaces were used, as well as Highly Oriented Pyrolytic Graphite (HOPG). Pd on Au supports is known to be active in the hydrogen evolution reaction (HER).…”

“…Here, we use a combination of electrochemical and microscopic techniques to determine the possible deposition mechanisms and their effect on the particle morphology. Electrochemical Scanning Tunneling Microscopy (EC‐STM) has already proven to be a powerful method to investigate in situ, at the local scale and under potential control the deposition of small Pd particles from simple salt solutions and their properties [24–29] . As supports, both reconstructed Au(111)–(22×√3) and unreconstructed Au(111)–(1×1) surfaces were used, as well as Highly Oriented Pyrolytic Graphite (HOPG).…”

Self-Assembly Process of Flatly Adsorbed Porphyrin Self-Assembled Monolayer on a Au(111) Surface Studied by ex situ Scanning Tunneling Microscopy and Electrochemical Reductive Desorption Measurements

“…The STM tip was a simply cut tungsten wire, of which the top was electrochemically sharpened in 0.6 M KOH, then insulated with nail polish. 54,55 All the STM images were obtained in the constant current mode (I tip : 0.30 nA, V sample : 0.30 V). Ex situ STM observation of the TMMPP SAM on the Au(111) was carried out in ultrapure water.…”