Structural Investigations of Electrode Surfaces

Abstract

A survey is given of the various ways in which information on the structure of electrode surfaces and their influence on the electrochemical behavior, especially on adsorption reactions, can be obtained. The techniques now at hand include a wide variety of spectroscopic methods, which are applicable in‐situ, such as reflectance spectroscopy over a broad range of photon energy, second harmonic generation, various X‐ray diffraction techniques and, most recently, scanning tunneling microscopy, which highlights the possibility of acquiring atomic‐scale resolution. In addition, the emersion of electrodes and their subsequent transfer into a vacuum chamber for detailed surface‐structural studies, e.g., by electron diffraction methods, is now widely used in electrochemistry, since it has been shown that electrodes can, in fact, be emersed with their electric double layer apparently intact. The combined venture incorporating all these techniques should lead to a truly microscopic description of electrochemical processes. The way in which structural information, even on an atomic scale, can be derived, is illustrated here by a few selected examples.

Durability evaluation of Ni‐Cr‐Mo super alloys in a simulated scrubbed flue gas environment

“…The test solution and the elevated exposure temperature simulated corrosion conditions of absorber upper zones, outlet ducts, reheat mixing zones and stacks in FGD plants. The solution formula was chosen from a number of electrolytes used for laboratory experiments simulating chosen FGD conditions [9][10][11][12]. Polarisation investigations have been carried out using the GAMRY INSTRUMENTS measurement card controlled by an IBM PC computer.…”

Structural changes during oxidation of Au(110)

“…The necessary requirements for a successful emersion experiment are a clean and atomically smooth surface (to ensure 'dry emersion') and the choice of emersion potential within the double-layer charging region. 25 Under these conditions and without specific adsorption the surface is hydrophobic and when emersed contains only the double-layer region, including the inner and outer Helmholtz layers. Excessive cycling into the oxidation region roughens the surface, causing it to become hydrophilic so that bulk electrolyte remains upon emersion.…”

Electrochemical nanoelectrodes for advanced investigations of nanostructures

“…The electrolyte consists of 5 mM CuSO 4 /100 mM H 2 SO 4 . The cyclic voltammogram corresponds to the data found in the literature [49,50]. The cyclic voltammogram of the tip fits exactly to that of a polycrystalline substrate in the same solution, only the current scales are orders of magnitude different (Fig.…”