scholarly journals Water-Involved Methane Selective Catalytic Oxidation by Dioxygen over Copper-Zeolites

2020 ◽  
Author(s):  
Lanlan Sun ◽  
Yu Wang ◽  
Chuanming Wang ◽  
Zaiku Xie ◽  
Naijia Guan ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Selective Oxidation ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
High Catalytic Activity ◽  
Oxidation Of Methane ◽  
Selective Catalytic Oxidation ◽  
Catalyst Temperature ◽  
Temperature Programmed ◽  
Space Time Yield

<p>The selective oxidation of methane to methanol is a dream reaction of direct methane functionalization, which remains a key challenge in catalysis and a hot issue of controversy. Herein, we report the water-involved methane selective catalytic oxidation by dioxygen over copper-zeolites. At 573 K, a state-of-the-art methanol space-time yield of 543 mmol/mol<sub>Cu</sub>/h with methanol selectivity of 91 % is achieved with Cu-CHA catalyst. Temperature-programmed surface reactions with isotope labelling determine water as the dominating oxygen and hydrogen source of hydroxyl in methanol while dioxygen participates in the reaction <a></a><a>through reducing to water</a>. Spectroscopic analyses reveal the fast redox cycle of Cu<sup>2+</sup>-Cu<sup>+</sup>-Cu<sup>2+</sup> during methane selective oxidation, which is closely related to the high catalytic activity of Cu-CHA. Density functional theory calculations suggest that both CuOH monomer and dimer in Cu-CHA can catalyze the selective oxidation of methane to methanol with Cu-OOH as the key reaction intermediate, and meanwhile, various copper sites undergo interconversion under reaction conditions.<br></p>

scholarly journals Water-Involved Methane Selective Catalytic Oxidation by Dioxygen over Copper-Zeolites

2020 ◽  
Author(s):  
Lanlan Sun ◽  
Yu Wang ◽  
Chuanming Wang ◽  
Zaiku Xie ◽  
Naijia Guan ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Selective Oxidation ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
High Catalytic Activity ◽  
Oxidation Of Methane ◽  
Selective Catalytic Oxidation ◽  
Catalyst Temperature ◽  
Temperature Programmed ◽  
Space Time Yield

<p>The selective oxidation of methane to methanol is a dream reaction of direct methane functionalization, which remains a key challenge in catalysis and a hot issue of controversy. Herein, we report the water-involved methane selective catalytic oxidation by dioxygen over copper-zeolites. At 573 K, a state-of-the-art methanol space-time yield of 543 mmol/mol<sub>Cu</sub>/h with methanol selectivity of 91 % is achieved with Cu-CHA catalyst. Temperature-programmed surface reactions with isotope labelling determine water as the dominating oxygen and hydrogen source of hydroxyl in methanol while dioxygen participates in the reaction <a></a><a>through reducing to water</a>. Spectroscopic analyses reveal the fast redox cycle of Cu<sup>2+</sup>-Cu<sup>+</sup>-Cu<sup>2+</sup> during methane selective oxidation, which is closely related to the high catalytic activity of Cu-CHA. Density functional theory calculations suggest that both CuOH monomer and dimer in Cu-CHA can catalyze the selective oxidation of methane to methanol with Cu-OOH as the key reaction intermediate, and meanwhile, various copper sites undergo interconversion under reaction conditions.<br></p>

CO oxidation by MoS2-supported Au19 nanoparticles: effects of vacancy formation and tensile strain

2016 ◽  
Vol 18 (19) ◽  
pp. 13232-13238 ◽  
Author(s):  
Soonho Kwon ◽  
Kihyun Shin ◽  
Kihoon Bang ◽  
Hyun You Kim ◽  
Hyuck Mo Lee
Keyword(s):  
Density Functional Theory ◽  
Co Oxidation ◽  
Catalytic Oxidation ◽  
Density Functional ◽  
Tensile Strain ◽  
Density Functional Theory Calculations ◽  
Vacancy Formation ◽  
Oxidation Of Co ◽  
Functional Theory ◽  
Catalytic Oxidation Of Co

The mechanism of the catalytic oxidation of CO activated by MoS2-supported Au19 nanoparticles (NPs) was studied using density functional theory calculations.

The interplay between structural perfectness and CO oxidation catalysis on aluminum, phosphorous and silicon complexes of corroles

2019 ◽  
Vol 21 (14) ◽  
pp. 7661-7674 ◽  
Author(s):  
Afshan Mohajeri ◽  
Nasim Hassani
Keyword(s):  
Density Functional Theory ◽  
Carbon Monoxide ◽  
Co Oxidation ◽  
Catalytic Oxidation ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Oxidation Catalysis ◽  
Functional Theory ◽  
Oxidation Of Carbon Monoxide

Catalytic oxidation of carbon monoxide on perfect and defective structures of corrole complexes with aluminum, phosphorous and silicon have been investigated by performing density functional theory calculations.

scholarly journals Synergistic Effects of Co3O4-CeO2 Nanoparticles towards Catalytic Oxidation of Aromatic Hydrocarbons: A Study in Association with Carbon Monoxide and Humidity

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Trung Dang-Bao ◽  
Hong Phuong Phan ◽  
Phung Anh Nguyen ◽  
Pham Phuong Trang Vo ◽  
Van Tien Huynh ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Synergistic Effects ◽  
Active Oxygen Species ◽  
High Dispersion ◽  
High Catalytic Activity ◽  
Impregnation Method ◽  
Temperature Programmed ◽  
The Stability

In this study, a series of Co3O4-CeO2 nanocomposites with various Co3O4 loading were fabricated by the impregnation method using cobalt(II) acetate as the cobalt precursor for the treatment of benzene, toluene, ethylbenzene, and xylene (BTEX). The as-prepared Co3O4-CeO2 nanocomposites were thoroughly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brumauer-Emmett-Teller (BET), hydrogen temperature-programmed reduction (H2-TPR), and temperature-programmed desorption (O2-TPD). The excellent reproduction of active oxygen species caused by the high dispersion of Co3O4 crystals on the CeO2 supports was established. In addition, the reduction peaks of Co3O4-CeO2 nanocomposites were found at much lower temperatures compared to pure CeO2, considering their unique redox property influencing on the high catalytic activity. Among the characterized materials, the 5.0 wt.% Co3O4 supported on CeO2 (5.0Co–Ce) was the best system for catalytic oxidation of xylene, along with excellent performances in the cases of benzene, ethylbenzene, and toluene. Its catalytic activity increased in the order: benzene < xylene < ethylbenzene < toluene . Furthermore, the addition of carbon monoxide (CO) as a coreactant permitted to improve the catalytic performances in such oxidations as well as the stability of as-prepared catalysts, even under humid conditions.

scholarly journals How to Extract Adsorption Energies, Adsorbateadsorbate Interaction Parameters, and Saturation Coverages from Temperature Programmed Desorption Experiments

2021 ◽  
Author(s):  
Sudarshan Vijay ◽  
Henrik Høgh Kristoffersen ◽  
Yu Katayama ◽  
Yang Shao-Horn ◽  
Ib Chorkendorff ◽  
...  
Keyword(s):  
Adsorption Energy ◽  
Density Functional ◽  
Configurational Entropy ◽  
Density Functional Theory Calculations ◽  
Temperature Programmed Desorption ◽  
Functional Theory ◽  
Interaction Terms ◽  
Saturation Coverage ◽  
Adsorption Energies ◽  
Temperature Programmed

<p>We present a simple scheme to extract the adsorption energy, adsorbate interaction parameter and the saturation coverage from temperature programmed desorption (TPD) experiments. We propose that the coverage dependent adsorption energy can be fit using a functional form including the configurational entropy and linear adsorbate-adsorbate interaction terms. As one example of this scheme, we analyze TPD spectra of desorption on Au(211) and Au(310) surfaces. We determine that under atmospheric pressure, the <i>steps</i> of both facets adsorb between 0.4-0.9 ML coverage of CO*. We show this result to be consistent with density functional theory calculations of adsorption energies with the BEEF-vdW functional. <b></b></p>

scholarly journals K-10 montmorillonite: An efficient and reusable catalyst for selective oxidation of aldehydes in the presence of dioxygen

2019 ◽  
Vol 8 (5) ◽  
pp. 380-389
Author(s):  
Ikram EL Amrani ◽  
Ahmed Atlamsani
Keyword(s):  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Selective Oxidation ◽  
Reusable Catalyst ◽  
Good Activity ◽  
Mild Conditions ◽  
Catalyst Temperature ◽  
Clay Catalyst ◽  
Excellent Selectivity

A commercial montmorillonite clay catalyst, K-10 montmorillonite, was tested for catalytic oxidation of aldehydes in the presence of molecular oxygen under mild conditions. K-10 montmorillonite catalysed the oxidation of aldehydes with good activity and excellent selectivity toward the formation of the corresponding acids. The effects of the amount of catalyst, temperature and solvent on the catalytic activity were investigated. Remarkably, this catalyst was reusable without any appreciable loss in activity and selectivity.

Modification of the catalytic properties of the Au4 nanocluster for the conversion of methane-to-methanol: synergistic effects of metallic adatoms and a defective graphene support

2015 ◽  
Vol 17 (15) ◽  
pp. 9706-9715 ◽  
Author(s):  
J. Sirijaraensre ◽  
J. Limtrakul
Keyword(s):  
Density Functional Theory ◽  
Catalytic Activity ◽  
Density Functional ◽  
Catalytic Properties ◽  
Synergistic Effects ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Oxidation Of Methane ◽  
The Density Functional Theory ◽  
Conversion Of Methane

By means of the density functional theory calculations, enhanced catalytic activity of Au4 cluster for the partial oxidation of methane with the N2O oxidant is observed when the cluster is deposited on top of the Pd/graphene.

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