scholarly journals Oxidation State and Symmetry of Magnesia-Supported Pd13Ox Nanocatalysts Influence Activation Barriers of CO Oxidation

2012 ◽  
Vol 134 (18) ◽  
pp. 7690-7699 ◽  
Author(s):  
Michael Moseler ◽  
Michael Walter ◽  
Bokwon Yoon ◽  
Uzi Landman ◽  
Vahideh Habibpour ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation State ◽  
Activation Barriers

A density functional theory study of the mechanisms of addition of transition metal oxides ReO3L(L = Cl-, O-, OCH3, CH3) to substituted ketenes

2015 ◽  
Vol 14 (05) ◽  
pp. 1550035 ◽  
Author(s):  
Issahaku Ahmed ◽  
Richard Tia ◽  
Evans Adei
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Metal Complexes ◽  
Oxidation State ◽  
Density Functional ◽  
High Activation ◽  
Functional Theory ◽  
Activation Barriers ◽  
Reaction Energies ◽  
Addition Pathway

Ketenes are excellent precursors for catalytic asymmetric reactions, creating chiral centers mainly through addition across their C = C bonds. Density functional theory (DFT) calculations at the MO6/LACVP* and B3LYP/LACVP* levels of theory were employed in a systematic investigation of the peri-, chemo- and regio-selectivity of the addition of transition metal oxo complexes of the type ReO 3 L ( L = Cl -, O -, OCH 3, CH 3) to substituted ketenes O = C = C ( CH 3)(X) [ X = CH 3, H , CN , Ph ] with the aim of elucidating the effects of substituents on the mechanism of the reactions. The [2 + 2] addition pathway across the C = C or C = O (depending on the ligand) is the most preferred in the reactions of dimethyl ketene with all the metal complexes studied. The [2 + 2] pathway is also the most preferred in the reactions of ReO 3 Cl with all the substituted ketenes studied except when X = Cl . Thus of all the reactions studied, it is only the reaction of ReO 3 Cl with O = C = C ( CH 3)( Cl ) that prefers the [3 + 2] addition pathway. Reactions of dimethyl ketene with ReO 3 L favors addition across C = O bonds of the ketene when L = O - and CH 3 but favors addition across C = C bonds when L = OCH 3 and Cl . In the reactions of ReO 3 Cl with substituted ketenes, addition across C = O bonds is favored only when X = H while addition across C = C bonds is favored when X = CH 3, Cl , Ph , CN . The reactions of dimethyl ketene with ReO 3 L will most likely lead to the formation of an ester precursor in each case. A zwitterionic intermediate is formed in the reactions except in the reactions of [Formula: see text]. The order in the activation energies of the reactions of dimethyl ketenes with the metal complexes ReO 3 L with respect to changing ligand L is O - < CH 3 O - < Cl - < CH 3 while the order in reaction energies is CH 3 < CH 3 O - < O - < Cl -. For the reactions of substituted ketenes with ReO 3 Cl , the order in activation barriers is CH 3 < Ph < CN < Cl < H while the reaction energies follow the order Cl < CH 3 < H < Ph < CN . In the reactions of dimethyl ketenes with ReO 3 L , the trend in the selectivity of the reactions with respect to ligand L is Cl - < CH 3 O - < CH 3 < O - while the trend in selectivity is CH 3 < CN < Cl < Ph in the reactions of ReO 3 Cl with substituted ketenes. It is seen that reactions involving a change in oxidation state of metal from the reactant to product have high activation barriers while reactions that do not involve a change in oxidation state have low activation barriers. For both [3 + 2] and [2 + 2] additions, low activation barriers are obtained when the substituent on the ketene is electron-donating while high activation barriers are obtained when the substituent is electron-withdrawing.

XANES investigation of the Co oxidation state in solution and in cancer cells treated with Co(III) complexes

2006 ◽  
Vol 100 (5-6) ◽  
pp. 963-971 ◽  
Author(s):  
Paul D. Bonnitcha ◽  
Matthew D. Hall ◽  
Clare K. Underwood ◽  
Garry J. Foran ◽  
Mei Zhang ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Cancer Cells ◽  
Oxidation State

Strain effects on the Co oxidation state and the oxygen dissociation activity in barium lanthanum cobaltite thin films on Y2O3 stabilized ZrO2

2020 ◽  
Vol 8 (13) ◽  
pp. 6283-6290
Author(s):  
A. Fluri ◽  
H. Kusaba ◽  
J. Druce ◽  
M. Döbeli ◽  
T. Lippert ◽  
...  
Keyword(s):  
Thin Films ◽  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Co Oxidation ◽  
Surface Activity ◽  
Oxidation State ◽  
Tensile Strain ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Oxygen Dissociation

Tensile strain increases surface activity of cobaltite cathode oxides like Ba(La)CoO3 for solid oxide fuel cells and electrolysers (SOFCs/SOECs).

scholarly journals Co oxidation state at LSC-YSZ interface in model solid oxide electrochemical cell

2021 ◽  
Vol 359 ◽  
pp. 115531
Author(s):  
Fabrizio Gaulandris ◽  
Luise Theil Kuhn ◽  
Jakob Birkedal Wagner ◽  
Simone Sanna ◽  
Søren Bredmose Simonsen
Keyword(s):  
Co Oxidation ◽  
Oxidation State ◽  
Electrochemical Cell ◽  
Solid Oxide

scholarly journals Sensitivity of CO oxidation toward metal oxidation state in ceria-supported catalysts: an operando DRIFTS-MS study

2016 ◽  
Vol 6 (3) ◽  
pp. 818-828 ◽  
Author(s):  
Andre Kaftan ◽  
Fabian Kollhoff ◽  
Thanh-Son Nguyen ◽  
Laurent Piccolo ◽  
Mathias Laurin ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation State ◽  
Supported Catalysts ◽  
The State ◽  
Gas Mixture ◽  
Metal Oxidation ◽  
Initial State ◽  
Oxygen Coverage ◽  
Catalyst Powder

CeO2 and Rh/CeO2 show CO to CO2 conversion according to the input gas mixture, independent of the state of the catalyst powder. Pt/CeO2 demonstrates additional dependence on the initial state of the catalyst (oxygen coverage/oxidation state).

scholarly journals Evolution of Mn and Co oxidation state on TbMn1–xCoxO3 compounds

2013 ◽  
Vol 430 ◽  
pp. 012102 ◽  
Author(s):  
V Cuartero ◽  
J Blasco ◽  
J García ◽  
S Lafuerza ◽  
G Subías
Keyword(s):  
Co Oxidation ◽  
Oxidation State

Cu Oxide Deposited on Shape-Controlled Ceria Nanocrystals for CO Oxidation: Influence of Interface-Driven Oxidation States on Catalytic Activity

2021 ◽  
Author(s):  
Kasala Prabhakar Reddy ◽  
Han Seul Choi ◽  
Daeho Kim ◽  
Ryong Ryoo ◽  
Jeong Y. Park
Keyword(s):  
Catalytic Activity ◽  
Heterogeneous Catalysis ◽  
Co Oxidation ◽  
Oxidation State ◽  
Oxidation States ◽  
Highly Active ◽  
Shape Controlled ◽  
The Relationship

The design of a catalyst with a highly active and stable oxidation state is of great interest in heterogeneous catalysis. Herein, the relationship between catalytic activity and oxidation state on...

Size-Dependent Oxidation State and CO Oxidation Activity of Tin Oxide Clusters

ACS Catalysis ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 451-456 ◽  
Author(s):  
Yusuke Inomata ◽  
Ken Albrecht ◽  
Kimihisa Yamamoto
Keyword(s):  
Co Oxidation ◽  
Oxidation State ◽  
Tin Oxide ◽  
Oxidation Activity ◽  
Size Dependent
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