scholarly journals Silica-supported isolated gallium sites as highly active, selective and stable propane dehydrogenation catalysts

2017 ◽  
Vol 8 (4) ◽  
pp. 2661-2666 ◽  
Author(s):  
Keith Searles ◽  
Georges Siddiqi ◽  
Olga V. Safonova ◽  
Christophe Copéret
Keyword(s):  
High Selectivity ◽  
Thermal Transformation ◽  
Single Site ◽  
Propane Dehydrogenation ◽  
Initial Activity ◽  
Highly Active

Single-site gallium centers, obtained via grafting of a molecular siloxide precursor on the surface of partially dehydroxylated silica followed and a thermal transformation, display high initial activity for propane dehydrogenation, (TOF 20 mol C3H6 per mol Ga per h), and high selectivity for propylene (≥93) over 20 h.

Vanadium-Chromium Oxide: Effective Catalysts for Ammoxidation of 3-Picoline

2013 ◽  
Vol 634-638 ◽  
pp. 624-627 ◽  
Author(s):  
Feng Jiang ◽  
Wei Xu ◽  
Lei Niu ◽  
Guo Min Xiao
Keyword(s):  
Raman Spectroscopy ◽  
Catalytic Activity ◽  
Chromium Oxide ◽  
Atmospheric Pressure ◽  
High Selectivity ◽  
Surface Acidity ◽  
N2 Adsorption ◽  
Composite Oxide ◽  
Highly Active

Bulk vanadium-chromium oxide (VCrO) catalyst was prepared and characterized by N2 adsorption, XRD, NH3-TPD, H2-TPR, and Raman spectroscopy. XRD and Raman results showed that the VCrO catalyst was a kind of VV-CrIII composite oxide mainly consisted of crystalline V2O5 and CrVO4-Ⅲ (orthorhombic). NH3-TPD and H2-TPR results revealed that this catalyst had negligible surface acidity, and was easily reduced due to the formation of CrVO4-Ⅲ. Their catalytic activity was evaluated in the ammoxidation of 3-picoline to nicotinonitrile. Catalytic results showed that the bulk VCrO catalyst was highly active and selective; the nicotinonitrile selectivity and yield was up to 96.1%, 88.2% respectively at atmospheric pressure and 360 °C. The high selectivity was related closely to the low surface acidity of the catalyst.

scholarly journals Highly active and selective oxygen reduction to H2O2 on boron-doped carbon for high production rates

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yang Xia ◽  
Xunhua Zhao ◽  
Chuan Xia ◽  
Zhen-Yu Wu ◽  
Peng Zhu ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Density Functional ◽  
High Selectivity ◽  
Density Functional Theory Calculations ◽  
Reduction Reaction ◽  
Production Rates ◽  
Practical Applications ◽  
Highly Active ◽  
Boron Doped ◽  
Oxidized Carbon

AbstractOxygen reduction reaction towards hydrogen peroxide (H2O2) provides a green alternative route for H2O2 production, but it lacks efficient catalysts to achieve high selectivity and activity simultaneously under industrial-relevant production rates. Here we report a boron-doped carbon (B-C) catalyst which can overcome this activity-selectivity dilemma. Compared to the state-of-the-art oxidized carbon catalyst, B-C catalyst presents enhanced activity (saving more than 210 mV overpotential) under industrial-relevant currents (up to 300 mA cm−2) while maintaining high H2O2 selectivity (85–90%). Density-functional theory calculations reveal that the boron dopant site is responsible for high H2O2 activity and selectivity due to low thermodynamic and kinetic barriers. Employed in our porous solid electrolyte reactor, the B-C catalyst demonstrates a direct and continuous generation of pure H2O2 solutions with high selectivity (up to 95%) and high H2O2 partial currents (up to ~400 mA cm−2), illustrating the catalyst’s great potential for practical applications in the future.

A phenanthroline-based porous organic polymer for the iridium-catalyzed hydrogenation of carbon dioxide to formate

2019 ◽  
Vol 7 (23) ◽  
pp. 14019-14026 ◽  
Author(s):  
Gunniya Hariyanandam Gunasekar ◽  
Sungho Yoon
Keyword(s):  
Carbon Dioxide ◽  
Functional Groups ◽  
Single Site ◽  
Organic Polymer ◽  
Selective Catalyst ◽  
Porous Organic Polymer ◽  
Highly Active ◽  
First Time ◽  
Hydrogenation Of Carbon Dioxide ◽  
Hydrogenation Of Co

A novel phenanthroline-functionalized porous organic polymer (phen-POP) has been designed, and prepared for the first time without other reactive functional groups in the polymer skeleton. Post-synthetic metalation of phen-POP with IrCl3 afforded a single-site, highly active and selective catalyst for the hydrogenation of CO2 to formate.

Propane Dehydrogenation over Pt Clusters Localized at the Sn Single-Site in Zeolite Framework

ACS Catalysis ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 818-828 ◽  
Author(s):  
Zhikang Xu ◽  
Yuanyuan Yue ◽  
Xiaojun Bao ◽  
Zailai Xie ◽  
Haibo Zhu
Keyword(s):  
Single Site ◽  
Propane Dehydrogenation ◽  
Zeolite Framework

scholarly journals Highly Active Trifloaluminate Ionic Liquids as Recyclable Catalysts for Green Oxidation of 2,3,6-Trimethylphenol to Trimethyl-1,4-Benzoquinone

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1469
Author(s):  
Piotr Latos ◽  
Agnieszka Siewniak ◽  
Natalia Barteczko ◽  
Sebastian Jurczyk ◽  
Sławomir Boncel ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ionic Liquids ◽  
High Selectivity ◽  
Active Phase ◽  
Catalytic Performance ◽  
Reaction Parameters ◽  
Multiwalled Carbon ◽  
Highly Active ◽  
Recyclable Catalysts ◽  
Fold Excess

An effective method for the synthesis of 2,3,6-trimethyl-1,4-benzoquinone via the oxidation of 2,3,6-trimethylphenol as the key step in the in the preparation of vitamin E was presented. An aqueous solution of H2O2 was used as the oxidant and Lewis acidic trifloaluminate ionic liquids [emim][OTf]-Al(OTf)3, χAl(OTf)3 = 0.25 or 0.15 as catalysts. Trifloaluminate ionic liquids were synthesised by the simple reaction between 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (triflate) [emim][OTf] and aluminium triflate used in sub-stoichiometric quantities. The influence of the reaction parameters on the reaction course, such as the amount and concentration of the oxidant, the amount of catalyst, the amount and the type of organic solvent, temperature, and the reaction time was investigated. Finally, 2,3,6-trimethyl-1,4-benzoquinone was obtained in high selectivity (99%) and high 2,3,6-trimethylphenol conversion (84%) at 70 °C after 2 h of oxidation using a 4-fold excess of 60% aqueous H2O2 and acetic acid as the solvent. The catalytic performance of trifloaluminate ionic liquids supported on multiwalled carbon nanotubes (loading of active phase: 9.1 wt.%) was also demonstrated. The heterogeneous ionic liquids not only retained their activity compared to the homogenous counterparts, but also proved to be a highly recyclable catalysts.

Highly Active Nanosized Anatase TiO2–x Oxide Catalysts In Situ Formed through Reduction and Ostwald Ripening Processes for Propane Dehydrogenation

ACS Catalysis ◽  
2020 ◽  
Vol 10 (24) ◽  
pp. 14678-14693
Author(s):  
Zean Xie ◽  
Tingting Yu ◽  
Weiyu Song ◽  
Jianmei Li ◽  
Zhen Zhao ◽  
...  
Keyword(s):  
Ostwald Ripening ◽  
Anatase Tio2 ◽  
Oxide Catalysts ◽  
Propane Dehydrogenation ◽  
Highly Active

scholarly journals Selective propane dehydrogenation with single-site CoII on SiO2 by a non-redox mechanism

2015 ◽  
Vol 322 ◽  
pp. 24-37 ◽  
Author(s):  
Bo Hu ◽  
Andrew “Bean” Getsoian ◽  
Neil M. Schweitzer ◽  
Ujjal Das ◽  
HackSung Kim ◽  
...  
Keyword(s):  
Single Site ◽  
Propane Dehydrogenation ◽  
Redox Mechanism

scholarly journals 6-Arylimino-2-(2-(1-phenylethyl)naphthalen-1-yl)-iminopyridylmetal (Fe and Co) Complexes as Highly Active Precatalysts for Ethylene Polymerization: Influence of Metal and/or Substituents on the Active, Thermostable Performance of Their Complexes and Resultant Polyethylenes

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4244 ◽  
Author(s):  
Wenhua Lin ◽  
Liping Zhang ◽  
Jiahao Gao ◽  
Qiuyue Zhang ◽  
Yanping Ma ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Single Crystal ◽  
Ethylene Polymerization ◽  
Active Species ◽  
Single Site ◽  
X Ray ◽  
X Ray Crystallography ◽  
Molecular Weights ◽  
Highly Active ◽  
Cobalt Center

A series of 6-arylimino-2-(2-(1-phenylethyl)naphthalen-1-yl)iminopyridines and their iron(II) and cobalt(II) complexes (Fe1–Fe5, Co1–Co5) were synthesized and routinely characterized as were Co3 and Co5 complexes, studied by single crystal X-ray crystallography, which individually displayed a distorted square pyramidal or trigonal bipyramid around a cobalt center. Upon treatment with either methyluminoxane (MAO) or modified methyluminoxane (MMAO), all complexes displayed high activities regarding ethylene polymerization even at an elevated temperature, enhancing the thermostability of the active species. In general, iron precatalysts showed higher activities than their cobalt analogs; for example, 10.9 × 106 g(PE) mol−1 (Co) h−1 by Co4 and 17.0 × 106 g(PE) mol−1 (Fe) h−1 by Fe4. Bulkier substituents are favored for increasing the molecular weights of the resultant polyethylenes, such as 25.6 kg mol−1 obtained by Co3 and 297 kg mol−1 obtained by Fe3. A narrow polydispersity of polyethylenes was observed by iron precatalysts activated by MMAO, indicating a single-site active species formed.

scholarly journals Strain in Silica-Supported Ga (III) Sites: Neither Too Much nor Too Little for Propane Dehydrogenation Catalytic Activity

2020 ◽  
Author(s):  
C. S. Praveen ◽  
A. P. Borosy ◽  
Christophe Copéret ◽  
Aleix Comas Vives
Keyword(s):  
Catalytic Activity ◽  
Propane Dehydrogenation ◽  
Intrinsic Activity ◽  
Dehydrogenation Reaction ◽  
The Road ◽  
Highly Active ◽  
Beta Hydride Elimination ◽  
Hydride Elimination ◽  
Single Site Catalysts ◽  
Highly Strained

<p>Well-defined Ga(III) sites on SiO<sub>2</sub> are highly active, selective, and stable catalysts in the propane dehydrogenation reaction. In this contribution, we evaluate the catalytic activity towards propane dehydrogenation of tri-coordinated and tetra-coordinated Ga(III) sites on SiO<sub>2</sub> by means of first principles calculations using realistic amorphous periodic SiO<sub>2</sub>models. We evaluated the three reaction steps in propane dehydrogenation, namely the C-H activation of propane to form propyl, the beta-hydride elimination transfer to form propene, and a Ga-hydride, and the H-H coupling to release H<sub>2</sub>, regenerating the initial Ga-O bond and closing the catalytic cycle. Our work shows how Brønsted-Evans-Polanyi relationships are followed for these three reaction steps on Ga(III) sites on SiO<sub>2</sub> and highlights the role of the strain of the reactive Ga-O pairs on such sites of realistic amorphous SiO<sub>2</sub> models. While highly strained sites are very reactive sites for the initial C-H activation, they are more difficult to regenerate. The corresponding less strained sites are not reactive enough, pointing to the need of a right balance in strain to be an effective site for propane dehydrogenation. Overall, our work provides an understanding of the intrinsic activity of acidic Ga single sites towards the propane dehydrogenation reaction and paves the road towards the design and prediction of better single-site catalysts on SiO<sub>2 </sub>for the propane dehydrogenation reaction.</p>

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