Adsorption of carbon monoxide on a SmOx film

Evidence for perimeter sites over SmOx-modified Rh(100) surface by CO chemisorption

“…The larger binding energy of CO species adsorbed at the periphery must result mainly from poor screening of the holes induced by photoemission processes. It indicates a lack of p*-back-donation and a very weak interaction of CO with the perimeter, similar to the results of CO adsorption on the SmOx/Ru(0 0 0 1) interface [34] and the SmOx film [36]. On interacting with the adjacent SmOx at the periphery of SmOx/Rh(1 0 0), a part of the CO species may exist on the surface in the form of surface carbonatelike species, as previously observed on the Sm/ Ru(0 0 0 1) surface [42].…”

“…4 suggests a weak adsorption of CO on the SmOx/Rh(1 0 0) model surface. Desorption of CO was observed at 125 K on a SmOx film after CO saturated adsorption at 105 K [36]. In that case, the Ru(0 0 0 1) surface was completely covered by the SmOx film, and thus no contribution from the Ru surface or the Ru/SmOx interface had to be taken into account on CO adsorption.…”

“…At saturation exposure of 5.0 L CO, the peak at 531.2 eV reaches its saturation and the shoulder features settle at 529.0 and 532.6 eV. CO adsorption on the SmOx film exhibited an intense feature at 537.6 eV for O 1s photoemission, indicating that CO species interacted with samarium atoms at oxygen vacancy defect sites [36]. The absence of the O 1s signal at such a high binding energy further confirms that CO does not adsorb directly on the SmOx film at the sample temperature higher than 130 K, in accordance with the results of C 1s XPS measurements.…”

“…Therefore the peak at 285.0 eV in our case is attributed to the CO species adsorbed on the SmOx-free Rh sites. On the SmOx film, a weakly bound CO species appeared with C 1s peak at approximately 291.8 eV, and it was desorbed at approximately 125 K in TPD measurements at a heating rate of 5 K/s [36]. Therefore the peak at 287.9 eV on the SmOx/Rh(1 0 0) surface is probably due to the CO species interacting with the SmOx/Rh(1 0 0) interface, not to the CO species directly on the SmOx islands.…”

Surface Characterization of Gallium Nitride Modified with Peptides before and after Exposure to Ionizing Radiation in Solution

“…A detailed examination of the O 1s data reveals the presence of three predominant peaks: one centered at 531.5 eV, which is attributed to the existence of oxides (Ga 2 O 3 ); a second at approximately 534.1 eV, assigned to the presence of hydroxide species (−OH); and in some instances a prominent third peak that was recorded at higher binding energy (537.6 eV). 55,58,59 There is a discrepancy in the literature regarding assignment of the third peak. One can postulate that the presence of this species is due to hydroxyl groups present on the surface of the samples.…”