scholarly journals A molten carbonate shell modified perovskite redox catalyst for anaerobic oxidative dehydrogenation of ethane

2020 ◽  
Vol 6 (17) ◽  
pp. eaaz9339 ◽  
Author(s):  
Yunfei Gao ◽  
Xijun Wang ◽  
Junchen Liu ◽  
Chuande Huang ◽  
Kun Zhao ◽  
...  
Keyword(s):  
Oxidative Dehydrogenation ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Molten Carbonate ◽  
Ethane Oxidation ◽  
Molten Layer ◽  
Functional Theory ◽  
Ethane Conversion ◽  
Redox Catalyst ◽  
Redox Active

Acceptor-doped, redox-active perovskite oxides such as La0.8Sr0.2FeO3 (LSF) are active for ethane oxidation to COx but show poor selectivity to ethylene. This article reports molten Li2CO3 as an effective “promoter” to modify LSF for chemical looping–oxidative dehydrogenation (CL-ODH) of ethane. Under the working state, the redox catalyst is composed of a molten Li2CO3 layer covering the solid LSF substrate. The molten layer facilitates the transport of active peroxide (O22−) species formed on LSF while blocking the nonselective sites. Spectroscopy measurements and density functional theory calculations indicate that Fe4+→Fe3+ transition is responsible for the peroxide formation, which results in both exothermic ODH and air reoxidation steps. With >90% ethylene selectivity, up to 59% ethylene yield, and favorable heat of reactions, the core-shell redox catalyst has an excellent potential to be effective for intensified ethane conversion. The mechanistic findings also provide a generalized approach for designing CL-ODH redox catalysts.

scholarly journals Understanding oxidative dehydrogenation of ethane on Co3O4 nanorods from density functional theory

2016 ◽  
Vol 6 (18) ◽  
pp. 6861-6869 ◽  
Author(s):  
Victor Fung ◽  
Franklin (Feng) Tao ◽  
De-en Jiang
Keyword(s):  
Density Functional Theory ◽  
Oxidative Dehydrogenation ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Rate Determining Step ◽  
Oxidative Dehydrogenation Of Ethane ◽  
Co3o4 Nanorods

Density functional theory calculations reveal the complete pathways of oxidative dehydrogenation of ethane to form ethene on the Co3O4(111) surface and the rate-determining step.

scholarly journals Photo-fluorination of nanodiamonds catalyzing oxidative dehydrogenation reaction of ethylbenzene

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhishan Luo ◽  
Qiang Wan ◽  
Zhiyang Yu ◽  
Sen Lin ◽  
Zailai Xie ◽  
...  
Keyword(s):  
Oxidative Dehydrogenation ◽  
Active Sites ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Dehydrogenation Reaction ◽  
Higher Temperature ◽  
Fe Catalysts ◽  
Dehydrogenation Of Ethylbenzene ◽  
Surface Fluorination

AbstractStyrene is one of the most important industrial monomers and is traditionally synthesized via the dehydrogenation of ethylbenzene. Here, we report a photo-induced fluorination technique to generate an oxidative dehydrogenation catalyst through the controlled grafting of fluorine atoms on nanodiamonds. The obtained catalyst has a fabulous performance with ethylbenzene conversion reaching 70% as well as styrene yields of 63% and selectivity over 90% on a stream of 400 °C, which outperforms other equivalent benchmarks as well as the industrial K−Fe catalysts (with a styrene yield of 50% even at a much higher temperature of ca. 600 °C). Moreover, the yield of styrene remains above 50% after a 500 h test. Experimental characterizations and density functional theory calculations reveal that the fluorine functionalization not only promotes the conversion of sp3 to sp2 carbon to generate graphitic layers but also stimulates and increases the active sites (ketonic C=O). This photo-induced surface fluorination strategy facilitates innovative breakthroughs on the carbocatalysis for the oxidative dehydrogenation of other arenes.

Redox-Active Heteroacene Chromophores Derived from a Non-Linear Aromatic Diimide

2019 ◽  
Author(s):  
Stella Luo ◽  
Kellie Stellmach ◽  
Stella Ikuzwe ◽  
Dennis Cao
Keyword(s):  
Density Functional Theory ◽  
Nucleophilic Substitution ◽  
Building Block ◽  
Density Functional ◽  
Organic Materials ◽  
Density Functional Theory Calculations ◽  
Differential Pulse ◽  
Fine Tuning ◽  
Functional Theory ◽  
Redox Active

<div>This work describes a three-step chromatography-free protocol for the synthesis of a novel organic materials</div><div>building block, dichlorinated mellophanic diimide (MDI), that is shown to undergo nucleophilic substitution</div><div>with a variety of ortho disubstituted benzenes to yield a series of chromophores. Furthermore, 1,2,4,5-</div><div>tetrasubstituted benzenes can be used to synthesize tetraimide heteropentacene derivatives endcapped by</div><div>MDI motifs. The fine-tuning effects of heteroatom identity were investigated by UV-Vis and fluorescence</div><div>spectroscopy, cyclic and differential pulse voltammetries, and density functional theory calculations. Oxidation</div><div>of diamino MDI derivatives yields di- and tetraimide functionalized azaacenes with significantly lowered LUMO</div><div>levels (down to –4.49 eV), narrowed bandgaps (down to 1.81 eV), and high molar absorptivities (up to 84,000</div><div>M<sup>–1</sup> cm<sup>–1</sup>).</div>

Redox-Active Heteroacene Chromophores Derived from a Non-Linear Aromatic Diimide

2019 ◽  
Author(s):  
Stella Luo ◽  
Kellie Stellmach ◽  
Stella Ikuzwe ◽  
Dennis Cao
Keyword(s):  
Density Functional Theory ◽  
Nucleophilic Substitution ◽  
Building Block ◽  
Density Functional ◽  
Organic Materials ◽  
Density Functional Theory Calculations ◽  
Differential Pulse ◽  
Fine Tuning ◽  
Functional Theory ◽  
Redox Active

<div>This work describes a three-step chromatography-free protocol for the synthesis of a novel organic materials</div><div>building block, dichlorinated mellophanic diimide (MDI), that is shown to undergo nucleophilic substitution</div><div>with a variety of ortho disubstituted benzenes to yield a series of chromophores. Furthermore, 1,2,4,5-</div><div>tetrasubstituted benzenes can be used to synthesize tetraimide heteropentacene derivatives endcapped by</div><div>MDI motifs. The fine-tuning effects of heteroatom identity were investigated by UV-Vis and fluorescence</div><div>spectroscopy, cyclic and differential pulse voltammetries, and density functional theory calculations. Oxidation</div><div>of diamino MDI derivatives yields di- and tetraimide functionalized azaacenes with significantly lowered LUMO</div><div>levels (down to –4.49 eV), narrowed bandgaps (down to 1.81 eV), and high molar absorptivities (up to 84,000</div><div>M<sup>–1</sup> cm<sup>–1</sup>).</div>

On the Linear Geometry of Lanthanide Hydroxide (Ln—OH, Ln=La-Lu)

2019 ◽  
Author(s):  
Hassan Harb ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Triple Bond ◽  
Density Functional ◽  
Valence Electron ◽  
Density Functional Theory Calculations ◽  
Electron Configuration ◽  
Functional Theory ◽  
Key Species ◽  
Pi Orbitals ◽  
Lanthanide Hydroxide ◽  
Linear Geometry

Lanthanide hydroxides are key species in a variety of catalytic processes and in the preparation of corresponding oxides. This work explores the fundamental structure and bonding of the simplest lanthanide hydroxide, LnOH (Ln=La-Lu), using density functional theory calculations. Interestingly, the calculations predict that all structures of this series will be linear. Furthermore, these results indicate a valence electron configuration featuring an occupied sigma orbital and two occupied pi orbitals for all LnOH compounds, suggesting that the lanthanide-hydroxide bond is best characterized as a covalent triple bond.

On the Linear Geometry of Lanthanide Hydroxide (Ln—OH, Ln=La-Lu)

2019 ◽  
Author(s):  
Hassan Harb ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Triple Bond ◽  
Density Functional ◽  
Valence Electron ◽  
Density Functional Theory Calculations ◽  
Electron Configuration ◽  
Functional Theory ◽  
Key Species ◽  
Pi Orbitals ◽  
Lanthanide Hydroxide ◽  
Linear Geometry

Lanthanide hydroxides are key species in a variety of catalytic processes and in the preparation of corresponding oxides. This work explores the fundamental structure and bonding of the simplest lanthanide hydroxide, LnOH (Ln=La-Lu), using density functional theory calculations. Interestingly, the calculations predict that all structures of this series will be linear. Furthermore, these results indicate a valence electron configuration featuring an occupied sigma orbital and two occupied pi orbitals for all LnOH compounds, suggesting that the lanthanide-hydroxide bond is best characterized as a covalent triple bond.

Sign in / Sign up

Export Citation Format

Share Document