Surface vicinity

Climent V, Garcia-Araez N, Henero E, Feliu JM. 2006. Potential of zero total charge of platinum single crystals A local approach to stepped surfaces vicinal to Pt(lll). Russ J Electrochem 42 1145-1160. 

The same surface species is obtained at ambient temperature by the reaction of Bu3SnH and the silanol groups, suggesting that the Sn-H bond is more reactive in this case than the Sn-C bond. The surface reaction depends upon the degree of dehydroxylation of the surface of silica. On silica dehydroxylated at 500°C the reaction leads to one well-defined surface complex. On the other hand, on silica dehydroxylated at 200°C, the evolution of alkane is continuous. The difference in the latter case is related to the presence of neighboring OH groups, because the number of the surface vicinal OH groups capable of... 

From gas phase measurements CO is known to prefer top sites on all three low index faces, with the CO molecule perpendicular to the surface and bonded through the carbon end of the molecule except at high coverages (27). It is likely that HCOOH and COOH are adsorbed in a similar way. It is not likely that they could "enter the "troughs , which seems to be possible for anions. For Pt(100) on the other hand, upon sweep reversal and gradual oxide reduction, anions are immediately adsorbed on that "flat" surface. They block adsorption of HCOOH. Adsorption of anions decreases as potential becomes more negative. The oxidation of HCOOH commences and the rate increases as at more negative potentials, i.e. at lower overpotential. A competition between anions and HCOOH adsorption explains this apparently anomalous behaviour. The explanation of the "anomalous behaviour of the Pt(110) surface can be also found in the data for stepped surface vicinal to the (100) and (110) orientations. 

The kinetic and dynamical aspects of the dissociative adsorption of 02 on the Pt(l 1 1), and surfaces vicinal to Pt(l 11), has been investigated in some detail. It provides a good example of precursor mediated dissociation, but is complicated by the fact that both physisorbed and chemisorbed molecular precursor states are involved, and access to the chemisorbed precursor is activated. It is also a good example of the role of step and defect sites in the overall conversion of the precursor states. The adsorption system has the advantage that the characterisation of a number of molecular and atomic states has also been the subject of considerable attention. 

Surfaces vicinal to fcc(l 11) and the miscut about the (112) direction, that is, with steps running along the dense (110 direction, still can differ. Due to ABC stacking, the fee [ 112 planes are not mirror planes and the minifacets at the steps... 

Nonequilibrium molecular dynamics for the interactimi parameters between alkylammonium alkylsulfonate ILs and an iron surface have been used [92] to develop a procedure for a quantitative prediction of the friction coefficient. Changes in the frictional force are explained in terms of the specific arrangements and orientations of groups forming the ionic liquid at the surface vicinity. 

For example, NH3-vapor as a reducing gas (electron donor), when contacting p-type PP film, causes a depletion of positive hole density in the near surface vicinity and therefore a corresponding reduction of its conductivity. On the other hand, NO2 as an electron acceptor increases the density of positive defects, resulting in conductivity enhancement [144]. Maximum chemical sensitivity is achieved by a polymer doping leading to the conductivity of semiconductors (ca. 10 to 10 Scm"0-... 

Solid-state Si MAS NMR spectra of MCF-A, APTES-MCF-A and APDMES-MCF-B are shown in Figure 3. The untonctionalised MCF-A, shows what appears to be three distinct peaks, which can be assigned as surface ganinal groups (Q ), surface vicinal silanol groups... 

Si02 powder used in the impregnation method was the sol-gel prepared Si02 atvarious pH, corresponding to the pH values used for sol-gel prepared catalysts (SG). From the results in Table 22-2, it was found that the pH of gelation strongly modified the porosity and surface area of the catalysts, but did not affect so much upon the dispersion of Pd atoms in the catalysts. The catalysts were conducted to methane combustion reaction, and the Pd/Si ratios at the surface vicinities of catalysts were measured by XPS before and after... 

A model accounting for changes in the surface concentration of kinks was developed by Heusler " from quantitative observations of the steady-state morphology for iron surface vicinal to (112) during anodic dissolution. He described the model as follows ... 

PDMS in the surface vicinity could not be obtained owing to the flexibility of the films. The preparation of cross sections near the free surface of PAS containing more than 41 wt% of PDMS by means of a cryosectioning method is in progress. 

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