Hydrophilic coadsorption

Coadsorption on Rh(lll) also modifies the HREELS features due to water.. As shown in Figure 3, a substantial sharpening and shift to 610 cm-1 of the pure D 0 band at 580 cm-1 (due to the superimposed D-0 IibraJion and Rh-0 stretch) correlates with the growth of the 650 cm-1 CO mode. The fact that the vibrational spectra of both species are modified by coadsorption suggests adsorption of water and CO onto adjacent sites, a form of hydrophilic coadsorption. 

HydrophiIic versus hydrophobic coadsorption. The contrast between the hydrophilic and hydrophobic coadsorption seen on Rh(111) and Pt(lll), if confirmed under normal electrochemical conditions, might be of electrocatalytic importance. On Rh(lll), where net attractive CO-HgO interactions produce a mixed phase in which CO is displaced to a three-fold binding site which is not occupied in the absence of water, CO and water appear to occupy adjacent binding sites. Such thorough mixing of the oxygen source (water) and the intermediate [or poison] (CO) should improve electrooxidation rates for C 0 H fuels (11). On Pt(lll), where net repulsions cause condensation of CO and water into separate patches, reaction between the adsorbed species could occur only at the boundaries between patches, and one would expect slower kinetics. 

O Brien. 1235 Ohmic drop, 811, 1089, 1108 Ohmic resistance, 1175 Ohm s law, 1127. 1172 Open circuit cell, 1350 Open circuit decay method, 1412 Order of electrodic reaction, definition 1187. 1188 cathodic reaction, 1188 anodic reaction, 1188 Organic adsorption. 968. 978. 1339 additives, electrodeposition, 1339 aliphatic molecules, 978, 979 and the almost-null current test. 971 aromatic compounds, 979 charge transfer reaction, 969, 970 chemical potential, 975 as corrosion inhibitors, 968, 1192 electrode properties and, 979 electrolyte properties and, 979 forces involved in, 971, 972 977, 978 free energy, 971 functional groups in, 979 heterogeneity of the electrode, 983, 1195 hydrocarbon chains, 978, 979 hydrogen coadsorption and, 1340 hydrophilicity and, 982 importance, 968 and industrial processes, 968 irreversible. 969. 970 isotherms and, 982, 983... 

Coadsorption of O2 and H2 O on Free and Supported Gold Clusters. It has been established experimentally that extended clean gold surfaces are hydrophilic [403]. The calculations showed that water adsorbs (relatively weakly) on free and supported Au clusters (Table 1.4), with adsorption energies that... 

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