CO adsorption on Al2O3-supported Pd clusters: XPS study

2000 ◽  
Vol 162-163 ◽  
pp. 679-684 ◽  
Author(s):  
V Johánek ◽  
I Stará ◽  
N Tsud ◽  
K Veltruská ◽  
V Matolı́n
Keyword(s):  
Co Adsorption ◽  
Pd Clusters ◽  
Xps Study ◽  
Supported Pd

Adsorption of Carbon Monoxide on Pd/SiO2/Si(111) Studied by Core-Level Photoemission

1998 ◽  
Vol 63 (11) ◽  
pp. 1793-1802 ◽  
Author(s):  
Zdeněk Bastl ◽  
Tomáš Šarapatka
Keyword(s):  
Carbon Monoxide ◽  
Photoelectron Spectroscopy ◽  
Co Adsorption ◽  
Charge Balance ◽  
Adsorption Activity ◽  
Chemical States ◽  
Adsorbed Co ◽  
Pd Clusters ◽  
Almost All ◽  
P Type

X-Ray photoelectron spectroscopy (XPS) has been used to study the adsorption of carbon monoxide on Pd dispersed on oxidized Si(111) surface. A fraction of the deposited Pd diffusing at room temperature to the SiO2/Si interface increases with decreasing SiO2 thickness. For oxide layers thinner than ≈1 nm, almost all deposited Pd diffuses to SiO2/Si interface forming there Si silicide. Consequently, the amount of adsorbed CO is dependent on the thickness of the thermally grown SiO2 layer. Two different chemical states of adsorbed carbon atoms, the population of which depends on the amount of the Pd deposited, are observed in the C (1s) spectra of adsorbed CO. Adsorption activity of Pd clusters does not depend on whether n- or p-type Si is used. Comparison of the experimental Pd/CO concentration ratios with those calculated assuming several different modes of the Pd growth on SiO2/Si points to the pseudo-Stranski-Krastanow mode (flat clusters with incomplete condensation of the first layer) at 300 K. Changes in charge balance across the Pd/SiO2/Si interface caused by CO adsorption are discussed in terms of the surface photovoltage effect and work function variation.

XPS Study of CO Adsorption on Simple Metals

1978 ◽  
Vol 17 (S2) ◽  
pp. 264 ◽  
Author(s):  
J. J. Pireaux ◽  
J. Ghijsen ◽  
J. Verbist ◽  
R. Caudano
Keyword(s):  
Co Adsorption ◽  
Xps Study

scholarly journals Influence of support morphology on the bonding of molecules to nanoparticles

2015 ◽  
Vol 112 (26) ◽  
pp. 7903-7908 ◽  
Author(s):  
Chi Ming Yim ◽  
Chi L. Pang ◽  
Diego R. Hermoso ◽  
Coinneach M. Dover ◽  
Christopher A. Muryn ◽  
...  
Keyword(s):  
Single Crystal ◽  
Surface Science ◽  
Heterogeneous Catalysts ◽  
Co Adsorption ◽  
Pd Nanoparticles ◽  
Metal Single Crystals ◽  
Supported Metal Nanoparticles ◽  
X Ray Absorption ◽  
Supported Pd ◽  
Identical Fashion

Supported metal nanoparticles form the basis of heterogeneous catalysts. Above a certain nanoparticle size, it is generally assumed that adsorbates bond in an identical fashion as on a semiinfinite crystal. This assumption has allowed the database on metal single crystals accumulated over the past 40 years to be used to model heterogeneous catalysts. Using a surface science approach to CO adsorption on supported Pd nanoparticles, we show that this assumption may be flawed. Near-edge X-ray absorption fine structure measurements, isolated to one nanoparticle, show that CO bonds upright on the nanoparticle top facets as expected from single-crystal data. However, the CO lateral registry differs from the single crystal. Our calculations indicate that this is caused by the strain on the nanoparticle, induced by carpet growth across the substrate step edges. This strain also weakens the CO–metal bond, which will reduce the energy barrier for catalytic reactions, including CO oxidation.

ChemInform Abstract: Growth/Restructuring of Pd Clusters Induced by CO Adsorption.

ChemInform ◽  
2010 ◽  
Vol 22 (46) ◽  
pp. no-no
Author(s):  
S. L. ANDERSON ◽  
T. MIZUSHIMA ◽  
Y. UDAGAWA
Keyword(s):  
Co Adsorption ◽  
Pd Clusters

Investigation of Carbon Monoxide Adsorption on Cationic Gold- Palladium Clusters

2013 ◽  
Vol 68 (10-11) ◽  
pp. 651-658 ◽  
Author(s):  
Yang-Mei Chen ◽  
Xiao-Yu Kuang ◽  
Xiao-Wei Sheng ◽  
Huai-Qian Wang ◽  
Peng Shao ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Molecular Orbital ◽  
Density Functional ◽  
Co Adsorption ◽  
Vibration Strength ◽  
Au Clusters ◽  
Highest Occupied Molecular Orbital ◽  
Lowest Unoccupied Molecular Orbital ◽  
Pd Clusters ◽  
Homo Lumo

Density functional calculations have been performed for the carbon monoxide molecule adsorption on AunPd+m(n+m ≤ 6) clusters. In the process of CO adsorption, small Au clusters and Pd clusters tend to be an Au atom and three Pd atoms adsorption, respectively. For the mixed Au-Pd clusters, an Au atom, a Pd atom, two atoms consisted of an Au atom and a Pd atom, two Pd atoms, and three Pd atoms adsorption structures are displayed. The highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps and natural bond orbital charge population are calculated. Moreover, CO adsorption energy, CO stretching frequency, and CO bond length (upon adsorption) are also analysed in detail. The results predict that the adsorption strength of Au clusters with CO and the C-O vibration strength is enhanced and reduced after doping of Pd in the AunPdmCO+ complexes, respectively

Sulfur resistance enhancement by grafted TiO2 in SiO2-supported Pd catalysts: Role of grafted TiO2 and genesis of Pd clusters

2009 ◽  
Vol 266 (1) ◽  
pp. 15-25 ◽  
Author(s):  
Hwo-Shuenn Sheu ◽  
Jyh-Fu Lee ◽  
Shin-Guang Shyu ◽  
Wha-Wen Chou ◽  
Jen-Ray Chang
Keyword(s):  
Sulfur Resistance ◽  
Pd Catalysts ◽  
Supported Pd Catalysts ◽  
Pd Clusters ◽  
Supported Pd
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