14-electron Rh and Ir silylphosphine complexes and their catalytic activity in alkene functionalization with hydrosilanes

2021 ◽  
Author(s):  
Niroshani Samitri Abeynayake ◽  
Julio Zamora-Moreno ◽  
Saidulu Gorla ◽  
Bruno Donnadieu ◽  
Miguel Muñoz ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Computational Study ◽  
Alkene Functionalization

Herein we report an experimental and computational study of a family of four coordinated 14-electron complexes of Rh(III) devoid of agostic interactions. The complexes [X-Rh(κ3(P,Si,Si)PhP(o-C6H4CH2SiiPr2)2], where X = Cl (Rh-1),...

scholarly journals Are All Single Atoms Created Equal? Surface Density Dependent Catalytic Activity of Single Pd Atoms Supported on Ceria

2021 ◽  
Author(s):  
Yongseon Kim ◽  
Gregory Collinge ◽  
Mal Soon Lee ◽  
Konstantin Khivantsev ◽  
Sung June Cho ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Density ◽  
Reaction Rate ◽  
Specific Activity ◽  
Computational Study ◽  
Single Atom ◽  
Cooperative Effects ◽  
Metal Atoms ◽  
Specific Catalytic Activity ◽  
Molecular Catalysts

The analogy between single atom catalysts (SACs) and molecular catalysts predicts that the specific catalytic activity of these systems is constant. We provide evidence that this prediction is not necessarily true. As a case in point, we show that the specific activity over ceria5 supported single Pd atoms linearly increases with metal atom density, originating from the cumulative enhancement of lattice oxygen mobility. The long-range electrostatic fingerprints (~1.5 nm) around each Pd site overlap with each other as surface Pd density increases, resulting in the observed deviation from constant specific activity. These cooperative effects exhaust previously active O atoms above a certain Pd density, leading to their permanent 10 removal and consequent drop in reaction rate. The findings of our combined experimental and computational study show that the specific catalytic activity of reducible oxide-supported single atom catalysts can be tuned by varying the surface density of single metal atoms.

scholarly journals In Search of the Active Sites for the Selective Catalytic Reduction on Tungsten-Doped Vanadia Monolayer Catalysts supported by TiO2

2021 ◽  
Author(s):  
Mengru Li ◽  
Sung Sakong ◽  
Axel Gross
Keyword(s):  
Catalytic Activity ◽  
Selective Catalytic Reduction ◽  
Active Sites ◽  
Density Functional ◽  
Catalytic Reduction ◽  
Computational Study ◽  
Critical Role ◽  
Operating Conditions ◽  
High Catalytic Activity ◽  
Atomistic Structure

Tungsten-doped vanadia-based catalysts supported on anatase TiO<sub>2</sub> are used to reduce hazardous NO emissions through the selective catalytic reduction of ammonia, but their exact atomistic structure is still largely unknown. In this computational study, the atomistic structure of mixed tungsta-vanadia monolayers on TiO<sub>2</sub> support under typical operating conditions has been addressed by periodic density functional theory calculations. The chemical environment has been taken into account in a grand-canonical approach. We evaluate the stable catalyst structures as a function of the oxygen chemical potential and vanadium and tungsten concentrations. Thus we determine structural motifs of tungsta-vanadia/TiO<sub>2</sub> catalysts that are stable under operating conditions. Furthermore, we identify active sites that promise high catalytic activity for the selective catalytic reduction by ammonia. Our calculations reveal the critical role of the stoichiometry of the tungsta-vanadia layers with respect to their catalytic activity in the selective catalytic reduction.

A computational study of CO oxidation reactions on metal impurities in graphene divacancies

2018 ◽  
Vol 20 (4) ◽  
pp. 2284-2295 ◽  
Author(s):  
Yanan Tang ◽  
Weiguang Chen ◽  
Zigang Shen ◽  
Chenggang Li ◽  
Dongwei Ma ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Density Functional ◽  
Computational Study ◽  
Density Functional Theory Calculations ◽  
Oxidation Reactions ◽  
Functional Theory ◽  
Metal Impurities ◽  
The Density Functional Theory

Based on the density functional theory calculations, the formation geometry, electronic properties, and catalytic activity of metal impurities in divacancy graphene (M-DG, M = Mo, Fe, Co, and Ni) were systematically investigated.

scholarly journals Are All Single Atoms Created Equal? Surface Density Dependent Catalytic Activity of Single Pd Atoms Supported on Ceria

2021 ◽  
Author(s):  
Yongseon Kim ◽  
Gregory Collinge ◽  
Mal Soon Lee ◽  
Konstantin Khivantsev ◽  
Sung June Cho ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Density ◽  
Reaction Rate ◽  
Specific Activity ◽  
Computational Study ◽  
Single Atom ◽  
Cooperative Effects ◽  
Metal Atoms ◽  
Specific Catalytic Activity ◽  
Molecular Catalysts

The analogy between single atom catalysts (SACs) and molecular catalysts predicts that the specific catalytic activity of these systems is constant. We provide evidence that this prediction is not necessarily true. As a case in point, we show that the specific activity over ceria5 supported single Pd atoms linearly increases with metal atom density, originating from the cumulative enhancement of lattice oxygen mobility. The long-range electrostatic fingerprints (~1.5 nm) around each Pd site overlap with each other as surface Pd density increases, resulting in the observed deviation from constant specific activity. These cooperative effects exhaust previously active O atoms above a certain Pd density, leading to their permanent 10 removal and consequent drop in reaction rate. The findings of our combined experimental and computational study show that the specific catalytic activity of reducible oxide-supported single atom catalysts can be tuned by varying the surface density of single metal atoms.

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