Carbon monoxide adsorption on supported ruthenium

Abstract

The infrared spectra of CO adsorbed on alumina-supported ruthenium catalysts reveal one band when the metal particles are large and three bands when the particles are small. One band is assigned to CO adsorbed on low index planes of the Ru, while two of the bands are associated with CO adsorbed on low coordination edge and corner metal atoms. Comparison of CO adsorption to H2 adsorption reveals CO/H ratios as high as 4 on Ru particles of 11 Á diameter implying multiple adsorption of CO on low coordination sites. This is supported by the observed CO stretching frequencies which approach the values reported for the known carbonyls of Ru. A simplified molecular orbital approach is applied to CO adsorption on Ru. This treatment is inadequate to explain the behavior of Ru and the differences observed between CO adsorption on Ru and Pt.Publication costs assisted by the National Science Foundation Absolute integrated molar absorption coefficients, A, have been measured for infrared absorption by all the fundamental vibrations of CFgl and for v% v%, 1/5, and of CFCI3 in the gas phase. These data are analyzed to determine the possibility of monitoring the infrared absorption to measure the extent of Freon contamination of the atmosphere by a remote sensing device. Although such an application may not be easy, it does appear to be feasible. The intensity values are compared with measurements of the absolute infrared intensities of other chlorofluoromethanes. An intensity sum rule is formulated and tested by the data for these molecules. Application of the rule to predict the intensities for an unknown molecule is illustrated for CFCIH2.

Methanation reaction on ruthenium thin films: a mechanistic investigation. [PhD. thesis]

“…Their data could be fit quite nicely using first order desorption kinetics 151 which are indicative of non-dissociated carbon monoxide. These results are in agreement with those of Madey and Menzel on ruthenium (0001).Several infrared studies involving carbon monoxide on supported ruthenium catalysts have been reported recently[112][113][114][115][116]. Each reports that the carbon monoxide molecule is non-dissociated on ruthenium.…”

“…f few of these would, however, not change the order dependence of the rate | law in the desired manner. If we examine equation (112) it is apparent that in order to increase the negative order dependence in terms of i hydrogen we must either change the rate limiting step such that the exponent of the hydrogen term in the numerator is less than +2 or we must add a term in the denominator which goes as the hydrogen pressure raised to a power greater than +3/2. The numerator has a very significant effect upon the fit of the theory to the data, especially in the positive order region of the hydrogen order plot.…”

Effect of the Crystallographic Phase of Ruthenium Nanosponges on Arene and Substituted‐Arene Hydrogenation Activity

“…In this case, strong binding of PCy 3 on the catalyst surface blocks the catalytically active sites. Additionally, carbon monoxide and thiophene were used separately as catalyst poisons, wherein suppression of catalytic activity was noted for carbon monoxide and thiophene treated catalyst (Ru‐TBAB). Since, ruthenium nanosponge exhibits good catalytic activity towards arene hydrogenation, it would be important to study the effect of alloying with other metals to understand the catalytic activity at moderate reaction conditions with lower catalyst loading.…”

Improved Performance of Ru/γ‐Al2O3 Catalysts in the Selective Methanation of CO in CO2‐Rich Reformate Gases upon Transient Exposure to Water‐Containing Reaction Gas

“…Comparable correlations between Ru particle size and the relative population of on-top and bridge-bonded adsorbed CO were also reported in an umber of previous studies. [41][42][43] This was explained by the formation of linearly bound CO ad species for adsorption on low-coordination edge and corner atoms, the relative contribution of whichi ncreasesw ith decreasing particles ize. [44,45] Another notable consequence of activation in wet reformatei st he lower coverage of surface formates rela- tive to that obtaineda fter activation in dry SR-ref 6000.…”