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.

scholarly journals Study on the adsorption selection of CH$$_4$$ on CuO (110) versus (111) surfaces: a density functional theory study

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Long Lin ◽  
Linwei Yao ◽  
Shaofei Li ◽  
Zhengguang Shi ◽  
Kun Xie ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Adsorption Capacity ◽  
Active Sites ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Density Functional Theory Calculations ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Strong Adsorption ◽  
Selection Of

AbstractFinding the active sites of suitable metal oxides is a key prerequisite for detecting CH$$_4$$ 4 . The purpose of the paper is to investigate the adsorption of CH$$_4$$ 4 on intrinsic and oxygen-vacancies CuO (111) and (110) surfaces using density functional theory calculations. The results show that CH$$_4$$ 4 has a strong adsorption energy of −0.370 to 0.391 eV at all site on the CuO (110) surface. The adsorption capacity of CH$$_4$$ 4 on CuO (111) surface is weak, ranging from −0.156 to −0.325 eV. In the surface containing oxygen vacancies, the adsorption capacity of CuO surface to CH$$_4$$ 4 is significantly stronger than that of intrinsic CuO surface. The results indicate that CuO (110) has strong adsorption and charge transfer capacity for CH$$_4$$ 4 , which may provide experimental guidance.

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 Gold Nanoclusters Grown on MoS2 Nanosheets by Pulsed Laser Deposition: An Enhanced Hydrogen Evolution Reaction

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7503
Author(s):  
Yuting Jing ◽  
Ruijing Wang ◽  
Qiang Wang ◽  
Xuefeng Wang
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Au Nanoparticles ◽  
Gold Nanoclusters ◽  
Density Functional Theory Calculations ◽  
Laser Deposition ◽  
Mos2 Nanosheets ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
A Current

Au nanoparticles were decorated on a 2H MoS2 surface to form an Au/MoS2 composite by pulse laser deposition. Improved HER activity of Au/MoS2 is evidenced by a positively shifted overpotential (−77 mV) at a current density of −10 mA cm−2 compared with pure MoS2 nanosheets. Experimental evidence shows that the interface between Au and MoS2 provides more sites to combine protons to form an active H atom. The density functional theory calculations found that new Au active sites on the Au and MoS2 interface with improved conductivity of the whole system are essential for enhancing HER activity of Au/MoS2.

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 The nature of active sites for carbon dioxide electroreduction over oxide-derived copper catalysts

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dongfang Cheng ◽  
Zhi-Jian Zhao ◽  
Gong Zhang ◽  
Piaoping Yang ◽  
Lulu Li ◽  
...  
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Heterogeneous Catalysts ◽  
Density Functional Theory Calculations ◽  
Copper Catalysts ◽  
Functional Theory ◽  
Surface Models ◽  
Cu Catalysts ◽  
Intense Debate

AbstractThe active sites for CO2 electroreduction (CO2R) to multi-carbon (C2+) products over oxide-derived copper (OD-Cu) catalysts are under long-term intense debate. This paper describes the atomic structure motifs for product-specific active sites on OD-Cu catalysts in CO2R. Herein, we describe realistic OD-Cu surface models by simulating the oxide-derived process via the molecular dynamic simulation with neural network (NN) potential. After the analysis of over 150 surface sites through NN potential based high-throughput testing, coupled with density functional theory calculations, three square-like sites for C–C coupling are identified. Among them, Σ3 grain boundary like planar-square sites and convex-square sites are responsible for ethylene production while step-square sites, i.e. n(111) × (100), favor alcohols generation, due to the geometric effect for stabilizing acetaldehyde intermediates and destabilizing Cu–O interactions, which are quantitatively demonstrated by combined theoretical and experimental results. This finding provides fundamental insights into the origin of activity and selectivity over Cu-based catalysts and illustrates the value of our research framework in identifying active sites for complex heterogeneous catalysts.

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