Infrared spectra of hydrocarbons chemisorbed on silica-supported metals. III. 1-butene on nickel and platinum over a range of temperatures

1969 ◽  
Vol 311 (1506) ◽  
pp. 415-427 ◽  
Keyword(s):  
Infrared Spectra ◽  
Spectral Intensity ◽  
Intensity Increase ◽  
Surface Species ◽  
Dissociative Chemisorption ◽  
Adsorbed Species ◽  
Supported Platinum ◽  
Surface Carbide ◽  
Surface Metal ◽  
Surface Metal Atom

Infrared spectra have been obtained of 1-butene chemisorbed on silica-supported platinum and nickel over the temperature range —78 to +95 °C. Virtually identical spectra were observed for 1-butene chemisorbed on platinum at — 78, 20 and 95 °C. The dominant spectral features at 2958, 2930 and 2870 cm -1 are assigned to associatively chemisorbed 1-butene, CH 3 —CH 2 —CHM—CH 2 M; a weaker band near 3010 cm -1 is attributed to olefinic surface species of the type MCH=CRM (M = surface metal atom; R — alkyl group). On hydrogenation most of the chemisorbed surface species were converted to n-butane, but at 95 °C a weak spectrum of chemisorbed w-butyl groups was observed. From the large spectral intensity increase on hydrogenation (eightfold to tenfold) it is concluded that considerable dissociative chemisorption must have occurred initially, probably to yield some surface carbide with a C 4 skeleton. A very similar spectrum, likewise attributed to an associatively adsorbed species (bands at 2958, 2920, 2870 cm -1 ), was obtained after chemisorption of 1-butene on nickel at — 78 °C. On hydrogenation at — 78 °C a large amount of n-butane was formed and the metal surface was virtually cleared of chemisorbed species. The spectral intensity increase on hydrogenation at — 78 °C was about 7.5-fold, indicating that the degree of initial dissociative chemisorption is about as great as that which occurred on platinum at all temperatures. However, after chemisorption at 20 or 95 °C, the spectra on nickel indicated that a greater number of CM bonds are formed and that some of the chemisorbed C 4 species may be attached to the surface at three or four of the carbon atoms. Also the amount of adsorption increased slowly with time. On hydrogenation at 20 °C only a small amount of n -butane was produced and many surface n -butyl groups were obtained. Also less dissociative chemisorption occurs on nickel at this temperature, for the spectral intensity increase on hydrogenation was about fourfold.

Infrared spectra of hydrocarbons chemisorbed on silica-supported metals. II. Ethylene on nickel and platinum over a range of temperatures

1969 ◽  
Vol 311 (1506) ◽  
pp. 391-413 ◽  
Keyword(s):  
Gas Phase ◽  
Infrared Spectra ◽  
Hydrogenation Reaction ◽  
Dissociative Adsorption ◽  
Spectral Intensity ◽  
Intensity Increase ◽  
Surface Species ◽  
Dissociative Chemisorption ◽  
Surface Carbide ◽  
Spectroscopic Feature

Infrared spectra have been obtained of ethylene chemisorbed on silica-supported nickel over the temperature range — 78 to 150 °C, and on platinum over the range —145 to +150 °C. Relatively similar spectra resulted when ethylene was chemisorbed on platinum at any temperature in the range down to —78 °C. The dominant spectral features at 2920, 2880 and 2795 cm -1 are assigned to associatively chemisorbed ethylene MCH 2 —CH 2 M (M = surface metal atom); a weaker band at 3010 cm -1 is attributed to surface MCH=CHM species. On hydrogenation, most of the chemisorbed surface species were converted to gaseous ethane, but at 95 °C and increasingly at 150 °C, a weak spectrum of chemisorbed n -butyl groups was observed. From the large spectral intensity increase on hydrogenation (about tenfold) it is concluded that considerable initial dissociative chemisorption must also have occurred, probably in the form of surface carbide. A different spectrum occurred on adsorption at —145 °C with a single strong band at 2907 cm -1 ; this is ascribed to M 2 CH—CHM 2 surface species, which revert at higher temperatures to those described above. The spectrum attributed to associatively chemisorbed ethylene on nickel (bands at 2870 and 2790 cm -1 ) was the dominant spectroscopic feature only after short initial periods of chemisorption at — 78 °C. After prolonged periods of chemisorption at — 78 °C, or shorter periods at 20 °C, the spectra indicated that surface dimerization was occurring, probably via a self-hydrogenation reaction; at 20 °C an appreciable number of n -butyl groups were gradually formed on the surface by this process. On hydrogenation at — 78 °C, ethane and a smaller amount of n -butane were formed, whereas at 20 °C the gas phase consisted of only a low pressure of n -butane; at both temperatures many chemisorbed n -butyl groups remained on the surface. Less dissociative adsorption occurs on nickel at those temperatures than on platinum as the spectral intensity increase on hydrogenation was about threefold. Extensive dissociation, probably to a carbide, occurs when ethylene is chemisorbed on nickel at 150 °C. A large spectral intensity increase occurs on hydrogenation at this temperature and methane is instantaneously detected in the gas phase. The latter grows in intensity over a period of hours at the expense of the chemisorbed species. The spectroscopically observable species appear to be attached to the metal surface by σ rather than by π bonds.

The infrared spectra of surface metal atom vibrations

1986 ◽  
Vol 209 (2) ◽  
pp. 387-390 ◽  
Author(s):  
Jianguo Li ◽  
John Daschbach ◽  
Jerry J. Smith ◽  
Michael D. Morse ◽  
Stanley Pons
Keyword(s):  
Metal Atom ◽  
Infrared Spectra ◽  
Surface Metal ◽  
Surface Metal Atom

Activating Metal Oxides Nanocatalysts for Electrocatalytic Water Oxidation by Quenching-Induced Near-Surface Metal Atom Functionality

2021 ◽  
Vol 143 (35) ◽  
pp. 14169-14177
Author(s):  
Changchun Ye ◽  
Juzhe Liu ◽  
Qinghua Zhang ◽  
Xiaojing Jin ◽  
Yun Zhao ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Metal Atom ◽  
Water Oxidation ◽  
Near Surface ◽  
Surface Metal ◽  
Surface Metal Atom

Quantitative analysis of infrared spectra of adsorbed species using transmission and diffuse reflectance modes

2009 ◽  
Vol 371 (1-2) ◽  
pp. 99-107 ◽  
Author(s):  
Julien Couble ◽  
Paul Gravejat ◽  
François Gaillard ◽  
Daniel Bianchi
Keyword(s):  
Quantitative Analysis ◽  
Infrared Spectra ◽  
Diffuse Reflectance ◽  
Adsorbed Species

scholarly journals Realization of N-Type Semiconducting of Phosphorene through Surface Metal Doping and Work Function Study

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Haocheng Sun ◽  
Yuan Shang ◽  
Yanmei Yang ◽  
Meng Guo
Keyword(s):  
Electronic Structure ◽  
Work Function ◽  
Valence Electron ◽  
Electron Configuration ◽  
Impurity States ◽  
Cu Doping ◽  
Na Doping ◽  
Surface Metal ◽  
Structure Engineering ◽  
Surface Metal Atom

Phosphorene becomes an important member of the layered nanomaterials since its discovery for the fabrication of nanodevices. In the experiments, pristine phosphorene shows p-type semiconducting with no exception. To reach its full capability, n-type semiconducting is a necessity. Here, we report the electronic structure engineering of phosphorene by surface metal atom doping. Five metal elements, Cu, Ag, Au, Li, and Na, have been considered which could form stable adsorption on phosphorene. These elements show patterns in their electron configuration with one valence electron in their outermost s-orbital. Among three group 11 elements, Cu can induce n-type degenerate semiconducting, while Ag and Au can only introduce localized impurity states. The distinct ability of Cu, compared to Ag and Au, is mainly attributed to the electronegativity. Cu has smaller electronegativity and thus denotes its electron to phosphorene, upshifting the Fermi level towards conduction band, resulting in n-type semiconducting. Ag and Au have larger electronegativity and hardly transfer electrons to phosphorene. Parallel studies of Li and Na doping support these findings. In addition, Cu doping effectively regulates the work function of phosphorene, which gradually decreases upon increasing Cu concentration. It is also interesting that Au can hardly change the work function of phosphorene.

Infrared Spectra of Hydroxyl Groups on the Surface of Platinum

1971 ◽  
Vol 49 (20) ◽  
pp. 3409-3410 ◽  
Author(s):  
B. A. Morrow ◽  
P. Ramamurthy
Keyword(s):  
Infrared Spectroscopy ◽  
Infrared Spectra ◽  
Platinum Oxide ◽  
The Other ◽  
Hydroxyl Groups ◽  
Supported Platinum

Infrared spectroscopy has been used to show that two types of PtOH species exist on the surface of silica-supported platinum. One of these is produced when O2 is allowed to react with hydrogen covered platinum (ν(OH) = 3497 cm−1) and the other is produced when H2O reacts with a reduced platinum oxide (ν(OH) = 3544 cm−1).

Sign in / Sign up

Export Citation Format

Share Document