Metal Electrodes Influence of Surface State and Structure

4 METAL ELECTRODES INFLUENCE OF SURFACE STATE AND STRUCTURE 

The catalytic activity of an electrode is determined not only by the natnre of the electrode metal (its bulk properties) but also by the composition and stmcture of the snr-face on which the electrochemical reaction takes place. These parameters, in tnm, depend on factors such as the method of electrode preparation, the methods of snr-face pretreatment, conditions of storage, and others, all having little effect on the bulk properties. 

The major factors that characterize the structure and state of catalyst surfaces and may influence tfieir activity are tfie crystallograpfiic orientation of the surface and of its individual segments, the presence of structural defects of different kinds or of 

The methods of X-ray diffraction usually were used to determine the orientation of crystal faces. Low-energy electron diffraction (LEED) gives more accurate results. However, such measurements provide an exact characterization only of the initial surface state of the electrodes. It is more difficult to determine the surface state after the electrochemical studies, and even more so during these studies. 

Many studies at single-crystal electrodes of xp-metals were directed at the special features of double-layer stracture and the potential of zero charge at the various single-crystal faces. It was shown that rather large differences could exist between the potentials of zero charge of different faces (see Table 10.1). 

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