In situ scanning tunnelling microscopy of a platinum {111} surface in aqueous sulphuric acid solution

Abstract

An in situ scanning tunnelling microscope was applied, for the first time, to a single-crystal platinum { 1 1 l} surface both before and after electrochemical potential cycling in aqueous sulphuric acid solution. The single-crystal Pt{ 11 l} was annealed in a flame near 1100 "C for 1 min and then quickly brought into contact with pure water. It was not possible to see any particular structures on the fire-annealed single crystal. It is shown that the fire-annealing procedure can produce an almost completely atomically flat surface on a single crystal. The flat { 11 l} surface of the Pt crystal was roughened by the electrochemical potential cycling. Semi-spherical domains have predominantly been observed on the single crystal. These domains seem to be randomly distributed over the surface. The diameter and heigbt of the semi-spherical domains were in the ranges 20-30 and 5-10A, respectively.

Scanning tunneling microscopy characterization of electrode materials in electrochemistry

“…Itaya and coworkers [56][57][58] performed continuously in situ STM measurement on polycrystalline Pt [56] and Pt(lI1) [57, 581 in aqueous sulfuric acid solution. They investigated the surface changes of polycrystalline Pt with electrode potential scanning from 0.4 V to -0.23V in 0.1 M H2S04 solution [56].…”

Synchrotron based operando surface X‐ray scattering study towards structure–activity relationships of model electrocatalysts

“…In the last decades, many spectroscopic and microscopic techniques have been adapted and developed by electrochemists to study the multi‐electron processes occurring on electrode surfaces as well as to track changes in surface composition, structure, and morphology. EC‐STM (Electrochemical Scanning Tunneling Microscopy), LEED (Low‐Energy Electron Diffraction) and AES (Auger Electron Spectroscopy) are examples of those commonly accepted surface science techniques adapted for electrochemistry . However, LEED and AES require ultra‐high vacuum (UHV) conditions to operate and involve sample transfer from liquid electrolyte to UHV, which increases the chance of contamination and induces changes in the sample environment.…”

“…Related electrocatalytic studies have shown that Pt(111) undergoes partial surface reconstruction under applied bias . Potential cycling in acidic electrolytes leads to formation of Pt islands mostly composed of (110) and (100) facets resulting in an increased H 2 evolution activity.…”

“…Related electrocatalytic studies have shown that Pt(111) undergoes partial surface reconstruction under applied bias . Potential cycling in acidic electrolytes leads to formation of Pt islands mostly composed of (110) and (100) facets resulting in an increased H 2 evolution activity. On the other hand, repeated polarization of the Pt surface with OER pulses to high positive potentials leads to the formation of core‐shell like Pt‐PtO x structures resulting in partial Pt dissolution along with a loss in HER activity …”

“…EC-STM (Electrochemical Scanning Tunneling Microscopy), LEED (Low-Energy Electron Diffraction) and AES (Auger Electron Spectroscopy) are examples of those com-monly accepted surface science techniques adapted for electrochemistry. [1][2][3][4][5][6][7][8] However, LEED and AES require ultra-high vacuum (UHV) conditions to operate and involve sample transfer from liquid electrolyte to UHV, which increases the chance of contamination and induces changes in the sample environment. Additionally, potential dependent changes on the surface (such as formation of intermediates or new layers) can be only recorded in-situ under electrochemical conditions by means of e. g. EC-STM, Raman and infrared spectroscopy, or ellipsometry.…”