The interaction of coadsorbed hydrogen and carbon monoxide on Ru(001)

Evidence of stable high-temperature Dx-CO intermediates on the Ru(0001) surface

“…With increasing θ CO , this desorption peak becomes progressively sharper and is confined to a narrower temperature range (∼275-350 K for θ CO > 1/3 ML) with a common leading edge, consistent with a repulsive interaction between D and CO. 10 ≤ 0.19 ML, all D 2 desorbs in a single peak and there is only a small region of overlap between the D 2 and CO desorption ranges. The shape of the D 2 traces for θ CO < 1/3 ML is consistent with those reported by Peebles et al 28 and by Diemant et al 23 for co-adsorbed layers produced by backfilling. For θ CO ≥ 0.35 ML, the low-temperature D 2 peak is fully desorbed prior to the onset of CO desorption.…”

Adsorption and reactions of CH2I2 on Ru(001) surface

“…This is in harmony with the tilting mechanism, as the macroscopic dipole adsorption on clean Ru(001) is 430 K at low coverage, which is shifted to lower temperatures moment, and Dw, depend on cos a, e.g. on the angle between the C 2 axis of the molecule and with increasing coverage [40,41]. This shift was also observed in our experiment ( Fig.…”

“…The more molecules are on the surface, the larger is the tilting angle, with tion, a new H 2 peak developed with T p =300 K at higher surface concentration of CH 2 I 2 , very likely the results that (i) bonding I atoms are not equivalent and the CH 2 I 2 molecule is in a stretched due to the influence of adsorbed iodine. It is known that coadsorbed species, like CO, forming a comconfiguration, and (ii) the partially positive C atoms of CH 2 I 2 become more open to nucleophilic pressed overlayer shift the desorption temperature of H 2 to lower temperature [40]. The other peak reactants, such as surface H. for H 2 appeared at 440-450 K, which may correspond to the decomposition of ethylidyne…”

CO adsorption on hydrogen saturated Ru(0001)

“…The coadsorption of H and CO has been studied by Peebles et al 23 They showed experimentally that the CO sticking probability drops with increasing deuterium coverage, meaning that deuterium acts as a site blocker for CO adsorption. There was no evidence for a chemical reaction between H and CO at 100 K and no additional thermal desorption states appear in the TDS.…”

“…23 Since the D-CO interaction is repulsive in the mixed overlayer and deuterium blocks adsorption sites, an interesting question is, how a gas phase CO molecule adsorbs in the H overlayer.…”