Photoemission and electron microscopy of small supported palladium clusters

1991 ◽  
Vol 245 (1-2) ◽  
pp. A138
Keyword(s):  
Electron Microscopy ◽  
Palladium Clusters ◽  
Supported Palladium

A quantum chemical study of hydrogen adsorption on carbon-supported palladium clusters

2019 ◽  
Vol 21 (38) ◽  
pp. 21577-21587 ◽  
Author(s):  
Lisa Warczinski ◽  
Christof Hättig
Keyword(s):  
Catalytic Hydrogenation ◽  
Quantum Chemical ◽  
Hydrogen Adsorption ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Palladium Clusters ◽  
Hydrogenation Reactions ◽  
Supported Palladium ◽  
Insight Into

A key step for achieving better insight into catalytic hydrogenation reactions is to understand in detail the process of hydrogen adsorption on the catalyst.

Direct UHV-TEM Observation of Palladium Clusters on a Silicon Surface

2004 ◽  
Vol 10 (1) ◽  
pp. 134-138 ◽  
Author(s):  
Masaki Takeguchi ◽  
Kazutaka Mitsuishi ◽  
Miyoko Tanaka ◽  
Kazuo Furuya
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Layer ◽  
Silicon Surface ◽  
Lattice Structure ◽  
Plan View ◽  
Palladium Clusters ◽  
Transmission Electron ◽  
Pd Clusters

About 1 monolayer of palladium was deposited onto a silicon (111) 7 × 7 surface at a temperature of about 550 K inside an ultrahigh vacuum transmission electron microscope, resulting in formation of Pd2Si nanoislands and a 1 × 1 surface layer. Pd clusters created from an excess of Pd atoms on the 1 × 1 surface layer were directly observed byin situplan view high-resolution transmission electron microscopy. When an objective aperture was introduced so that electron diffractions less than 0.20 nm were filtered out, the lattice structure of the 1 × 1 surface with 0.33 nm spacing and the Pd clusters with a trimer shape were visualized. It was found that image contrast of the 1 × 1 lattice on the specific height terraces disappeared, and thereby an atomic structure of the Pd clusters was clearly observed. The appearance and disappearance of the 1 × 1 lattice was explained by the effect of the kinematical diffraction. It was identified that a Pd cluster was composed of three Pd atoms without a centered Si atom, which is consistent with the model proposed previously. The feature of the Pd clusters stuck at the surface step was also described.

Structural Investigation of Palladium Clusters on γ-AlO3(111)/NiAl(110) with Transmission Electron Microscopy

Langmuir ◽  
1999 ◽  
Vol 15 (16) ◽  
pp. 5309-5313 ◽  
Author(s):  
S. A. Nepijko ◽  
M. Klimenkov ◽  
M. Adelt ◽  
H. Kuhlenbeck ◽  
R. Schlögl ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Investigation ◽  
Palladium Clusters ◽  
Transmission Electron

scholarly journals Altervalent cation-doped MCM-41 supported palladium catalysts and their catalytic properties

2011 ◽  
Vol 76 (6) ◽  
pp. 923-932 ◽  
Author(s):  
Haihui Jiang ◽  
Ligang Gai ◽  
Yan Tian
Keyword(s):  
Electron Microscopy ◽  
Palladium Catalysts ◽  
Xrd Analysis ◽  
Molar Ratio ◽  
Pd Catalysts ◽  
Transmission Electron ◽  
Supported Pd Catalysts ◽  
Supported Palladium ◽  
Mcm 41 ◽  
Supported Pd

Metal cation-doped MCM-41 (M-MCM-41, M=Al, Ce, Co, V, or Zr) supported Pd catalysts (Pd/M-MCM-41) were prepared by a solution-based reduction method. The catalysts were characterized by Xray diffraction (XRD) analysis, infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and further evaluated by selective hydrogenation of parachloronitrobenzene (p-CNB) in anhydrous ethanol. The metal cationcontaining Pd catalysts can efficiently enhance the selectivity for parachloroaniline (p-CAN). The highest selectivity of 96.5 % in the molar distribution for p-CNB to p-CAN was acquired over Pd (1.8 wt. %)/VMCM- 41 (Si/V=30, molar ratio) catalyst, and the corresponding turnover frequency (TOF) was 1.24?10-2 mol p-CNB mol-1 Pd s-1. Water molecules adsorbed by the support have important effects on both the catalytic activity of the sample and the selectivity for p-CAN. A water molecule-mediated catalytic hydrogenation is discussed.

scholarly journals Preparation of Mesoporous Silica-Supported Palladium Catalysts for Biofuel Upgrade

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Ling Fei ◽  
Harvind Kumar Reddy ◽  
Joshua Hill ◽  
Qianglu Lin ◽  
Bin Yuan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mesoporous Silica ◽  
Palladium Catalysts ◽  
Methyl Esters ◽  
Catalyst Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Cnts Surface ◽  
Supported Palladium

We report the preparation of two hydrocracking catalysts Pd/CoMoO4/silica and Pd/CNTs/CoMoO4/silica (CNTs, carbon nanotubes). The structure, morphologies, composition, and thermal stability of catalysts were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and thermogravimetric analysis (TGA). The catalyst activity was measured in a Parr reactor with camelina fatty acid methyl esters (FAMEs) as the feed. The analysis shows that the palladium nanoparticles have been incorporated onto mesoporous silica in Pd/CoMoO4/silica or on the CNTs surface in Pd/CNTs/CoMoO4/silica catalysts. The different combinations of metals and supports have selective control cracking on heavy hydrocarbons.

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