Clarifying the impacts of surface hydroxyls on CO oxidation on CeO2(100) surfaces: a DFT+U study

2020 ◽  
Vol 22 (15) ◽  
pp. 7738-7746
Author(s):  
Hui Zhou ◽  
Dong Wang ◽  
Xue-Qing Gong
Keyword(s):  
Heterogeneous Catalysis ◽  
Co Oxidation ◽  
Common Phenomenon ◽  
Reaction Conditions ◽  
Surface Hydroxyls ◽  
Surface Hydroxylation

In heterogeneous catalysis, surface hydroxylation is well recognized as a common phenomenon under realistic reaction conditions.

Synergistic effect of co-reactant promotes one-step oxidation of cyclohexane into adipic acid catalyzed by manganese porphyrins

2015 ◽  
Vol 93 (7) ◽  
pp. 696-701 ◽  
Author(s):  
Hui Li ◽  
Yuanbin She ◽  
Haiyan Fu ◽  
Meijuan Cao ◽  
Jing Wang ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Co Oxidation ◽  
Adipic Acid ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Catalyst Structure ◽  
Manganese Porphyrins ◽  
Co Oxidation Reaction ◽  
One Step ◽  
Acid Catalyzed

The synergistic effect of cyclohexane and cyclohexanone promoted synthesis of adipic acid catalyzed by [MnIIIT(p-Cl)PP]Cl with cyclohexane and cyclohexanone as co-reactants. The results showed that the conversions of cyclohexane and cyclohexanone were significantly enhanced because of the cyclohexanone synergistic effect, and the higher selectivity to adipic acid was obtained with dioxygen as an oxidant. The studies indicated that the co-oxidation of cyclohexane and cyclohexanone was influenced by the initial molar ratio of cyclohexanone and cyclohexane, catalyst structure, catalyst concentrations, and reaction conditions. The preliminary mechanism of the co-oxidation reaction of cyclohexane and cyclohexanone using [MnIIIT(p-Cl)PP]Cl as the catalyst was proposed.

scholarly journals Heterogeneous acidic catalysts for the tetrahydropyranylation of alcohols and phenols in green ethereal solvents

2018 ◽  
Vol 14 ◽  
pp. 1655-1659 ◽  
Author(s):  
Ugo Azzena ◽  
Massimo Carraro ◽  
Gloria Modugno ◽  
Luisa Pisano ◽  
Luigi Urtis
Keyword(s):  
Organic Chemistry ◽  
Heterogeneous Catalysis ◽  
Important Class ◽  
Green Solvents ◽  
Reaction Products ◽  
Reaction Conditions ◽  
One Pot ◽  
Acidic Catalysts ◽  
Set Up ◽  
Work Up

The application of heterogeneous catalysis and green solvents to the set up of widely employed reactions is a challenge in contemporary organic chemistry. We applied such an approach to the synthesis and further conversion of tetrahydropyranyl ethers, an important class of compounds widely employed in multistep syntheses. Several alcohols and phenols were almost quantitatively converted into the corresponding tetrahydropyranyl ethers in cyclopentyl methyl ether or 2-methyltetrahydrofuran employing NH4HSO4 supported on SiO2 as a recyclable acidic catalyst. Easy work up of the reaction mixtures and the versatility of the solvents allowed further conversion of the reaction products under one-pot reaction conditions.

Surface hydroxylation induced by alkaline-earth metal doping in NiO nanocrystals and its application in achieving a wide temperature operation window for preferential CO oxidation

2018 ◽  
Vol 5 (10) ◽  
pp. 2368-2381 ◽  
Author(s):  
Huixia Li ◽  
Liping Li ◽  
Shaofan Fang ◽  
Jianghao Wang ◽  
Shaoqing Chen ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Preferential Co Oxidation ◽  
Wet Impregnation ◽  
Surface Hydroxylation ◽  
Nio Nanocrystals ◽  
Co Precipitation ◽  
Low Pt Loading

A series of Pt/Ni1−xMgxO catalysts with a low Pt loading of 0.5 wt% are prepared by multistep co-precipitation and annealing processes followed by wet impregnation.

FTIR investigation under reaction conditions during CO oxidation over Ru(x)-CeO2 catalysts

2020 ◽  
Vol 493 ◽  
pp. 111086
Author(s):  
E. Gonzalez-A ◽  
R. Rangel ◽  
A. Solís-Garcia ◽  
A.M. Venezia ◽  
T.A. Zepeda
Keyword(s):  
Co Oxidation ◽  
Reaction Conditions ◽  
Ftir Investigation

scholarly journals High-temperature heterogeneous catalysis in platinum nanoparticle – molten salt suspensions

2020 ◽  
Vol 10 (3) ◽  
pp. 625-629
Author(s):  
Behzad Tangeysh ◽  
Clarke Palmer ◽  
Horia Metiu ◽  
Michael J. Gordon ◽  
Eric W. McFarland
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
High Temperature ◽  
Heterogeneous Catalysis ◽  
Co Oxidation ◽  
Molten Salt ◽  
Platinum Nanoparticles ◽  
Platinum Nanoparticle ◽  
Oxidation Activity

Suspensions of platinum nanoparticles (PtNPs) were formed in molten LiCl–LiBr–KBr via thermal decomposition of H2PtCl6, and subsequently evaluated for thermal stability and CO oxidation activity.

scholarly journals CO Oxidation on Stepped Rh Surfaces: μm-Scale Versus Nanoscale

2019 ◽  
Vol 150 (3) ◽  
pp. 605-612 ◽  
Author(s):  
Y. Suchorski ◽  
I. Bespalov ◽  
J. Zeininger ◽  
M. Raab ◽  
M. Datler ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation Reaction ◽  
Active Surface ◽  
Reaction Conditions ◽  
Miller Index ◽  
Co Oxidation Reaction ◽  
Catalytically Active ◽  
Field Emission Microscopy ◽  
Photoemission Electron

Abstract The catalytic CO oxidation reaction on stepped Rh surfaces in the 10−6 mbar pressure range was studied in situ on individual μm-sized high-Miller-index domains of a polycrystalline Rh foil and on nm-sized facets of a Rh tip, employing photoemission electron microscopy (PEEM) and field-ion/field-emission microscopy (FIM/FEM), respectively. Such approach permits a direct comparison of the reaction kinetics for crystallographically different regions under identical reaction conditions. The catalytic activity of the different Rh surfaces, particularly their tolerance towards poisoning by CO, was found to be strongly dependent on the density of steps and defects, as well as on the size (µm vs. nm) of the respective catalytically active surface. Graphic Abstract

scholarly journals Combining Planar Laser-Induced Fluorescence with Stagnation Point Flows for Small Single-Crystal Model Catalysts: CO Oxidation on a Pd(100)

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 484 ◽  
Author(s):  
Jianfeng Zhou ◽  
Sebastian Matera ◽  
Sebastian Pfaff ◽  
Sara Blomberg ◽  
Edvin Lundgren ◽  
...  
Keyword(s):  
Single Crystal ◽  
Co Oxidation ◽  
Flow Reactor ◽  
Laser Induced Fluorescence ◽  
Model Catalysts ◽  
Stagnation Flow ◽  
Reaction Conditions ◽  
Planar Laser Induced Fluorescence ◽  
Planar Laser ◽  
Crystal Model

A stagnation flow reactor has been designed and characterized for both experimental and modeling studies of single-crystal model catalysts in heterogeneous catalysis. Using CO oxidation over a Pd(100) single crystal as a showcase, we have employed planar laser-induced fluorescence (PLIF) to visualize the CO2 distribution over the catalyst under reaction conditions and subsequently used the 2D spatially resolved gas phase data to characterize the stagnation flow reactor. From a comparison of the experimental data and the stagnation flow model, it was found that characteristic stagnation flow can be achieved with the reactor. Furthermore, the combined stagnation flow/PLIF/modeling approach makes it possible to estimate the turnover frequency (TOF) of the catalytic surface from the measured CO2 concentration profiles above the surface and to predict the CO2, CO and O2 concentrations at the surface under reaction conditions.

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