Surface preparation electrochemical

Frankenthal, R. P., The Effect of Surface Preparation on Pitting and Anodic Dissolution of Iron-Chromium Alloys , J. Electrochem. Soc., 114, 201c (1967)... 

It was found that the intensity of Co2ps/2 decreased significantly (by a factor of 2.5), supporting the concept of Co dissolution from the alloy and formation of the Pt skin layer on the electrode surface during electrochemical stabilization. As shown in Fig. 10.4b, a clear CL shift was stUl observed in the Pt4/7/2 spectmm for the stabilized Pt-Co, in spite of the dissolution of Co, although the CL shift after stabilization was slightly smaller (0.15 eV) than in the as-prepared alloy (0.19 eV). Thus, we... 

The experiments were performed in a combined system for UHV and electrochemical measurements. It consists of a UHV system equipped with standard facilities for surface preparation and characterization and a pocket-size scanning tunneling microscope (STM) [Kopatzki, 1994], a pre-chamber containing a flow cell for electrochemical measurements, which was attached to the main UHV system via a gate valve, and... 

The influence of Pt modihcations on the electrochemical and electrocatalytic properties of Ru(OOOl) electrodes has been investigated on structurally well-defined bimetallic PtRu surfaces. Two types of brmetalhc surfaces were considered Ru(OOOl) electrodes covered by monolayer Pt islands and monolayer PtRu/Ru(0001) surface alloys with a highly dispersed and almost random distribution of the respective surface atoms, with different Pt surface contents for both types of structures. The morphology of these surfaces differs significantly from that of brmetaUic PtRu surfaces prepared by electrochemical deposition of Pt on Ru(0001), where Pt predominantly exists in small multilayer islands. The electrochemical and electrocatal5d ic measurements, base CVs, and CO bulk oxidation under continuous electrolyte flow, led to the following conclusions ... 

In contrast to the successful implementation of the bead method in studying the anomalous features, the contributions from studies with UHV-electrochemical systems has been limited to just a few. Subsequent work from our apparatus following corroboration of Clavilier s results concentrated on the effect of potential cycling through "oxide formation potential on the surface structure (19). and later on the effect of pH and type of anion (Wagner, F.T. Ross, P.N., J. Electroanal. Chem.. in press) on the anomalous features. Using the system in Yeager s laboratory, Hanson (20) was able to reproduced Clavilier s voltammetry not only for the (111) surface, but also the (100) and (110) surfaces as well. In spite of the relatively small number of contributions to the literature that have come from the UHV-electrochemical systems, they have made and essential validation of the bead method of surface preparation, and have verified the structure sensitivity of the anomalous features inferred from purely electrochemical observations. 

Figure 66D was obtained for the same CdTe(lll) crystal after electrochemical reduction at -2.0 V for 2 minutes. Transitions for both Cd and Te are evident, and the Cd/Te peak height ratio is similar to that observed by other workers for stoichiometric CdTe [393,394]. In addition, well-ordered (1 X 1) LEED patterns (Fig. 67) were observed on both the CdTe(lll)-Cd and CdTe(lll)-Te faces. This is in contrast to CdTe surfaces prepared by ion bombardment, where postbombardment annealing was required to produce a LEED pattern, and the annealing appeared to result in formation of a reconstructed surface. In summary, well-ordered, clean, and unreconstructed CdTe surfaces have been produced using a wet etching/electrochemical treatment. 

Wu et al. have studied adsorption and reaction of 2-iodoethanol [177] and acetaldehyde [178] on Ag(lll). Doubovaet al. [179] have studied adsorption of amyl alcohol on Ag(lll) electrodes in 0.05 M KGIO4 solutions and explained the observed differences and inconsistencies in the light of the applied experimental technique (e.g. the role of ac frequency) and the electrode surface preparation procedure. Generally, amyl alcohol was adsorbed less on Ag(lll) than on Hg. The electron-induced surface reactions of methyl formate [180] and methanol [181] on Ag(l 11) have been studied by Schwaner and White. Foresti et al. [182] have investigated electrochemically, adsorption of 1,5-pentanediol on the Ag(lll) and Ag(llO) faces. 

Many different types of techniques for protein immobilization have been developed using, in most cases, enzyme sensors. Early studies of enzyme biosensors often employed thick polymer membranes (thickness 0.01-1 mm) in which enzymes are physically entrapped or chemically anchored. The electrode surface was covered with the enzyme-immobilized polymer membranes to prepare electrochemical enzyme sensors. Although these biosensors functioned appropriately to... 

Surface Preparation The Established Superiority of Electrochemical Techniques... 

As with all surface analytical methods, surface preparation is critical to obtaining reproducible SHG from metallic surfaces and single crystals in particular. For surfaces prepared in UHV and then transferred to an electrochemical cell, sputtering and heating or annealing followed by Auger analysis of impurities should proceed inert transfer. Low energy electron diffraction (LEED) can also be used to check surface order. Metal electrode surfaces, particularly for the rotational anisotropy ex-... 

Fig. 48. The surface patter of Si02 stripes on a silicon wafer was prepared electrochemically by applying a bias pulse to locally remove the terminal hydrogen atoms. The aspect ratio (height/width) of oxide lines improves significantly when the relative humidity is lowered from 61% to 14%. Reproduced from [445]...

A more favourable approach is the incorporation of the active species in an electrically conducting polymer layer which then acts as an (electrical) intermediate between the electrode surface and the catalyst. Polypyrrole is considered to be especially suitable because it is acceptably stable under ambient conditions (2), has a high conductivity and can be easily prepared electrochemically from a great variety of solvent systems, including aqueous solutions (3-5). The catalytic species that have been applied in such polypyrrole-based systems comprise metal particles (6-9), metal chelates (10-13) (with anionic side groups) and enzymes (14-18). 

One may expect that future work on the electrochemistry of diamond should take two paths, namely, an extensive investigation (search for new processes and applications of the carbon allotropes in the electrochemical science and engineering) and intensive one (elucidation of the reaction mechanisms, revealing the effects of crystal structure and semiconductor properties on the electrochemical behavior of diamond and related materials). It is expected that better insight into these effects will result in the development of standard procedures for thin-film-electrodes growth, their characterization, and surface preparation. 

The Li surface preparation is very important. Immersion of Li electrodes covered by native films leads to complicated surface film replacement processes that may form a highly nonhomogeneous metal-solution interphase. In situ electrochemical surface preparation by dissolution or deposition may form very rough surfaces whose impedance spectra may be difficult to interpret properly. Hence, it seems that the most preferred way of studying the electrochemical behavior of a Li electrode in a specific solution is by using Li surfaces freshly and smoothly prepared in solutions. 

Cha SY, Lee WM (1999) Performance of proton exchange membrane fuel cell electrodes prepared by direct deposition of ultrathin platinum on the membrane surface. J Electrochem Soc 146 4055-60... 

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