Support effects on electronic structure of platinum clusters in Y zeolite

1991 ◽  
Vol 95 (10) ◽  
pp. 4070-4074 ◽  
Author(s):  
Mahesh G. Samant ◽  
Michel Boudart
Keyword(s):  
Electronic Structure ◽  
Y Zeolite ◽  
Support Effects ◽  
Platinum Clusters

Electronic structure of small palladium and platinum clusters

1985 ◽  
Vol 113 (5) ◽  
pp. 457-462 ◽  
Author(s):  
E. Miyoshi ◽  
Y. Sakai ◽  
S. Mori
Keyword(s):  
Electronic Structure ◽  
Platinum Clusters

scholarly journals Controlling the Adsorption of Carbon Monoxide on Platinum Clusters by Dopant-Induced Electronic Structure Modification

2016 ◽  
Vol 55 (37) ◽  
pp. 11059-11063 ◽  
Author(s):  
Piero Ferrari ◽  
Luis M. Molina ◽  
Vladimir E. Kaydashev ◽  
Julio A. Alonso ◽  
Peter Lievens ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Electronic Structure ◽  
Structure Modification ◽  
Platinum Clusters

scholarly journals Influence atoms of Co, Ni, Cu on the catalytic activity of small Pt clasters: First principles calculations

2020 ◽  
Vol 21 (3) ◽  
pp. 415-419
Author(s):  
O. M. Chernikova ◽  
H. D. Mateik ◽  
Y. V. Ogorodnik
Keyword(s):  
Electronic Structure ◽  
Catalytic Activity ◽  
Band Gap ◽  
First Principles ◽  
Valence Electron ◽  
Electronic Energy ◽  
Energy Spectra ◽  
First Principles Calculations ◽  
Research Systems ◽  
Platinum Clusters

Based on the calculations from the first principles, we obtained the distributions of valence electron densities and electronic energy spectra for small Ptn clusters (where n = 1-5 atoms). According to the results of calculations, it is determined that the inclusion of oxygen atoms or atoms of other kinds in small Ptn clusters, as a rule, affect the catalytic activity of research systems. It is established that during doping of small platinum clusters by atoms of 3-d transition metals (Cu, Ni, Co), the electronic structure of the cluster and the band gap change. This in turn helps to increase the catalytic activity of platinum.

scholarly journals Controlling the Adsorption of Carbon Monoxide on Platinum Clusters by Dopant-Induced Electronic Structure Modification

2016 ◽  
Vol 128 (37) ◽  
pp. 11225-11229 ◽  
Author(s):  
Piero Ferrari ◽  
Luis M. Molina ◽  
Vladimir E. Kaydashev ◽  
Julio A. Alonso ◽  
Peter Lievens ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Electronic Structure ◽  
Structure Modification ◽  
Platinum Clusters

Electronic Structure of Monodispersed Deposited Platinum Clusters

1991 ◽  
pp. 83-87
Author(s):  
P. Fayet ◽  
W. Eberhardt ◽  
D. M. Cox ◽  
Z. Fu ◽  
R. Sherwood ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Platinum Clusters

EELS Measurement of the Local Electronic Structure of Copper Atoms Segregated to Aluminum Grain Boundaries

1996 ◽  
Vol 54 ◽  
pp. 342-343
Author(s):  
S.J. Splinter ◽  
J. Bruley ◽  
P.E. Batson ◽  
D.A. Smith ◽  
R. Rosenberg
Keyword(s):  
Electronic Structure ◽  
Grain Boundaries ◽  
Boundary Segregation ◽  
Thin Layers ◽  
Nominal Composition ◽  
Spatially Resolved ◽  
Service Lifetime ◽  
Heat Treated ◽  
Probe Size ◽  
Local Electronic Structure

It has long been known that the addition of Cu to Al interconnects improves the resistance to electromigration failure. It is generally accepted that this improvement is the result of Cu segregation to Al grain boundaries. The exact mechanism by which segregated Cu increases service lifetime is not understood, although it has been suggested that the formation of thin layers of θ-CuA12 (or some metastable substoichiometric precursor, θ’ or θ”) at the boundaries may be necessary. This paper reports measurements of the local electronic structure of Cu atoms segregated to Al grain boundaries using spatially resolved EELS in a UHV STEM. It is shown that segregated Cu exists in a chemical environment similar to that of Cu atoms in bulk θ-phase precipitates.Films of 100 nm thickness and nominal composition Al-2.5wt%Cu were deposited by sputtering from alloy targets onto NaCl substrates. The samples were solution heat treated at 748K for 30 min and aged at 523K for 4 h to promote equilibrium grain boundary segregation. EELS measurements were made using a Gatan 666 PEELS spectrometer interfaced to a VG HB501 STEM operating at 100 keV. The probe size was estimated to be 1 nm FWHM. Grain boundaries with the narrowest projected width were chosen for analysis. EDX measurements of Cu segregation were made using a VG HB603 STEM.

An analytical microscopic study of metals in fluidized catalytic cracking catalyst

1986 ◽  
Vol 44 ◽  
pp. 854-855
Author(s):  
Clifford S. Rainey
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Acid Sites ◽  
Y Zeolite ◽  
Fcc Catalyst ◽  
Fluidized Catalytic Cracking ◽  
High Regeneration

The spatial distribution of V and Ni deposited within fluidized catalytic cracking (FCC) catalyst is studied because these metals contribute to catalyst deactivation. Y zeolite in FCC microspheres are high SiO2 aluminosilicates with molecular-sized channels that contain a mixture of lanthanoids. They must withstand high regeneration temperatures and retain acid sites needed for cracking of hydrocarbons, a process essential for efficient gasoline production. Zeolite in combination with V to form vanadates, or less diffusion in the channels due to coke formation, may deactivate catalyst. Other factors such as metal "skins", microsphere sintering, and attrition may also be involved. SEM of FCC fracture surfaces, AEM of Y zeolite, and electron microscopy of this work are developed to better understand and minimize catalyst deactivation.

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