The Effect of Surface Coverage on the Spectra of Chemisorbed CO.

Surface Centres for CO Adsorption on Supported Platinum

“…Spectrum a in Figure 1 exhibits Eischens et al 1956). The third band was attributed to a bridged CO species adsorbed on Pt 0 atoms (Herz and Shinouskis 1984; Datka and Eischens 1991).…”

“…Bands are observed below the frequencies for gaseous CO (2143 cm -1 ) as a result of the donation of electron density from the metal to the 2p* antibonding orbitals of the CO molecules upon adsorption. The increased electron density in the antibonding orbital of the CO molecule weakens the C-O bond and reduces its frequency (Herz and Shinouskis 1984).…”

Pd/SiO2-Cogelled Aerogel Catalysts and Impregnated Aerogel and Xerogel Catalysts: Synthesis and Characterization

“…In order to calculate the dispersion D (that is, the atomic ratio between the number of surface Pd atoms (Pd s ) and the number of total Pd atoms) from CO chemisorption measurements, the stoichiometric ratio CO/Pd s has to be known. It has been shown that CO chemisorption on Pd can occur in two ways (17,18): a carbon monoxide molecule can be bonded through the carbon to one Pd atom (linear CO) or to two Pd atoms (bridged CO). The ratio of linearly held CO to bridged-bonded CO decreases as the dispersion decreases (19,20) and the result of this is an increase in the global ratio CO/Pd s with dispersion.…”

Ion-dipole interactions between adsorbed CO and support cations in Pt/K-LTL

“…The assignment of CO absorption bands is complicated by the effects of particle size, dipolar coupling, CO-support interactions and electronic changes in the metal structure which are reflected in the shift of CO stretching frequency from its gasphase value [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”