Ultrahigh-vacuum-based experimental

Figure 44 Schematic of the experimental arrangement for electrochemical measurements of hydrogen-terminated boron-doped diamond (BDD) films in a Li+-based solid polymer electrolyte in ultrahigh vacuum (UHV). (From Ref. 67.)...

A proper judgment of the validity of these findings, as well as any extension of such work, must rest upon a detailed appreciation of the experiments involved. It is the aim of this article to review the experimental methods upon which these advances have been based—the flash filament technique, flash desorption, field emission and field ion microscopy, and the use of ultrahigh vacuum procedures. 

Electrochemical surface science has undergone rapid development in recent years due to the adaptation of ultrahigh-vacuum- (UHV-) based experimental techniques such as low-energy electron diftaction (LEED), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and high-resolution electron energy loss spectroscopy (HREELS). These techniques have allowed the establishment of a direct correlation between the composition and structure of the electrode surface and the mechanism of electrode processes. The adaptation of these techniques has buttressed a variety of classical electrochemical techniques that demand theoretical models in order to arrive at a semblance of mechanistic features at the atomic level. 

The active dissolution of iron in acidic media has been the subject of a very large number of papers for the last 40 years. All the reaction mechanisms are based on the generally agreed-upon experimental evidence that the dissolution rate increases with the solution pH at potentials well below the onset of passivity processes. The apparently unacceptable participation of hydroxyl ions in the reaction at these low pH values can be related to the strong dissociative power of transition metals with respect to water, an assumption supported for Fe by experimental evidence in ultrahigh vacuum [66]. Both groups of mechanisms stem from a common initial hydrolysis step assumed to be at equilibrium ... 

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