Adsorption of methane on single metal atoms supported on graphene: Role of electron back-donation in binding and activation

2020 ◽  
Vol 153 (24) ◽  
pp. 244701
Author(s):  
Nurapati Pantha ◽  
Kanchan Ulman ◽  
Shobhana Narasimhan
Keyword(s):  
Metal Atoms ◽  
Back Donation ◽  
Adsorption Of Methane

scholarly journals Oxidation of Ethanol in Cu-Faujasites Studied by IR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2669
Author(s):  
Łukasz Kuterasiński ◽  
Jerzy Podobiński ◽  
Jerzy Datka
Keyword(s):  
Ethanol Oxidation ◽  
Produced Water ◽  
Acid Sites ◽  
No Adsorption ◽  
Ir Studies ◽  
Oxygen Donor ◽  
Before And After ◽  
Acetate Formation ◽  
Back Donation

In this study, IR studies of the coadsorption of ethanol and CO on Cu+ cations evidenced the transfer of electrons from ethanol to Cu+, which caused the lowering of the frequency of the band attributed to CO bonded to the same Cu+ cation due to the more effective π back donation of d electrons of Cu to antibonding π* orbitals of CO. The reaction of ethanol with acid sites in zeolite HFAU above 370 K produced water and ethane, polymerizing to polyethylene. Ethanol adsorbed on zeolite Cu(2)HFAU containing acid sites and Cu+exch also produced ethene, but in this case, the ethene was bonded to Cu+ and did not polymerize. C=C stretching, which is IR non-active in the free ethene molecule, became IR active, and a weak IR band at 1538 cm−1 was present. The reaction of ethanol above 370 K in Cu(5)NaFAU zeolite (containing small amounts of Cu+exch and bigger amounts of Cu+ox, Cu2+exch and CuO) produced acetaldehyde, which was further oxidized to the acetate species (CH3COO-). As oxygen was not supplied, the donors of oxygen were the Cu species present in our zeolite. The CO and NO adsorption experiments performed in Cu-zeolite before and after ethanol reaction evidenced that both Cu+ox and Cu2+ (Cu2+exch and CuO) were consumed by the ethanol oxidation reaction. The studies of the considered reaction of bulk CuO and Cu2O as well as zeolites, in which the contribution of Cu+ox species was reduced by various treatments, suggest that ethanol was oxidized to acetaldehyde by Cu2+ox (the role of Cu+ox could not be elucidated), but Cu+ox was the oxygen donor in the acetate formation.

Cyano-Functionalized Porphyrins on Cu(111) from One-Dimensional Wires to Two-Dimensional Molecular Frameworks: On the Role of Co-Deposited Metal Atoms

2020 ◽  
Vol 32 (5) ◽  
pp. 2114-2122
Author(s):  
Alisson Ceccatto dos Santos ◽  
Rodrigo Cezar de Campos Ferreira ◽  
Juan Carlos Moreno-López ◽  
Lucas Barreto ◽  
Michael Lepper ◽  
...  
Keyword(s):  
Two Dimensional ◽  
One Dimensional ◽  
Metal Atoms ◽  
Deposited Metal

Inside Cover: Directionality of Dihydrogen Bonds: The Role of Transition Metal Atoms (ChemPhysChem 11/2012)

ChemPhysChem ◽  
2012 ◽  
Vol 13 (11) ◽  
pp. 2618-2618
Author(s):  
Oleg A. Filippov ◽  
Natalia V. Belkova ◽  
Lina M. Epstein ◽  
Agusti Lledos ◽  
Elena S. Shubina
Keyword(s):  
Transition Metal ◽  
Metal Atoms ◽  
Dihydrogen Bonds ◽  
Transition Metal Atoms

ChemInform Abstract: The Role of Back-Donation in Carbocation Chemistry

ChemInform ◽  
2001 ◽  
Vol 32 (4) ◽  
pp. no-no
Author(s):  
R. Lopez ◽  
E. Del Rio ◽  
M. I. Menendez ◽  
T. L. Sordo
Keyword(s):  
Back Donation

The Effect of Metal Atoms and Ligand Combinations in Organometallics on Excimer Laser Photoproducts and Yields

1988 ◽  
Vol 131 ◽  
Author(s):  
Y. Zhang ◽  
M. Stuke
Keyword(s):  
Mass Spectrometry ◽  
Laser Radiation ◽  
Gas Phase ◽  
Excimer Laser ◽  
Systematic Study ◽  
Ionization Mass ◽  
Laser Ionization ◽  
Metal Atoms ◽  
Excimer Laser Radiation

ABSTRACTA systematic study to find the role of different metal atoms and ligand combinations on the yield of the photoproducts generated upon irradiation of gas phase organometallics (i.e. metalalkyls) by uv excimer laser radiation was performed using laser ionization mass spectrometry.

METAL ATOMS IN CARBON NANOTUBES AND RELATED NANOPARTICLES

2001 ◽  
Vol 15 (31) ◽  
pp. 4037-4069 ◽  
Author(s):  
F. BANHART ◽  
N. GROBERT ◽  
M. TERRONES ◽  
J.-C. CHARLIER ◽  
P. M. AJAYAN
Keyword(s):  
Carbon Nanotubes ◽  
Tight Binding ◽  
Formation Mechanisms ◽  
Production Methods ◽  
Metal Atoms ◽  
In Situ Electron Microscopy ◽  
State Of Research ◽  
Walled Carbon Nanotubes

The paper reviews the present state of research in the field of metal-carbon nanocomposites and the interaction of metal atoms with graphitic structures. Metal crystals can be encapsulated within graphitic shells of cylindrical, spherical, or other geometry. Various chemical and physical production methods to generate metal containing carbon nanotubes and possible microscopic formation mechanisms are presented. In this context, the role of metals as catalysts in the formation of single-walled carbon nanotubes is discussed. The interaction of metal atoms with the graphitic lattice is of particular interest. In situ electron microscopy is used to study the behaviour of individual metal atoms in a graphitic lattice. Furthermore, novel nanostructures can be generated under electron irradiation. Finally, an overview of theoretical studies using molecular dynamics and tight binding calculations of the carbon-metal interaction is given.

An Atomic View of Surface Diffusion on Metals

1985 ◽  
Vol 57 ◽  
Author(s):  
Gert Ehrlich
Keyword(s):  
Diffusion Process ◽  
Metal Surfaces ◽  
Mean Square Displacement ◽  
Surface Transport ◽  
Specific Effects ◽  
Metal Atoms ◽  
The Status ◽  
Considerable Detail ◽  
Field Ion Microscope

AbstractAtomic migration in crystals is obscured by the crystal itself, and it has therefore taken ingenious indirect methods to study the diffusion process. In contrast, diffusion at surfaces is amenable to fairly direct examination, on the atomic level, through the use of the field-ion microscope. By combining measurements of the mean-square displacement with determinations of the distance distribution function, considerable detail about atomic jumps in diffusion can be obtained. Here we will briefly review results obtained by field-ion microscopic examination of single metal atoms and metal clusters diffusing on metal crystals.What is noteworthy in the diffusion of single metal atoms is the variety of behavior which is dictated by the nature of the substrate, and the occasional complexity of the diffusion process. Examples of substrate-specific effects in atomic migration will be given for both fcc and bcc metals. Another surprising aspect of diffusion on metal surfaces is the role of clusters. These are stable at relatively high temperatures, and often diffuse at rates comparable to those of single atoms. The status of such cluster studies will be briefly examined, not only for their significance in surface transport, but also for their interest in understanding cohesion at metal surfaces.

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