Direct dehydrogenation of isobutane to isobutene over Zn-doped ZrO2 metal oxide heterogeneous catalysts

2018 ◽  
Vol 8 (19) ◽  
pp. 4916-4924 ◽  
Author(s):  
Yang Liu ◽  
Chengjie Xia ◽  
Qi Wang ◽  
Lei Zhang ◽  
Ao Huang ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Heterogeneous Catalysts ◽  
First Time

A series of unconventional nano-sized Zn-doped ZnZrO-x catalysts are applied for the first time to the direct dehydrogenation of isobutane to isobutene.

Dissolution and Performing Homogeneous Photocatalysis of Polymeric Carbon Nitride

2018 ◽  
Author(s):  
Chaofeng Huang ◽  
Jing Wen ◽  
Yanfei Shen ◽  
Fei He ◽  
Li Mi ◽  
...  
Keyword(s):  
Conjugated Polymer ◽  
Carbon Nitride ◽  
Heterogeneous Catalysts ◽  
Methane Sulfonic Acid ◽  
Environment Friendly ◽  
The Poor ◽  
Catalytic Sites ◽  
Homogeneous Photocatalysis ◽  
Polymeric Carbon ◽  
First Time

<a></a><a>As a metal-free conjugated polymer, carbon nitride (CN) has attracted tremendous attention as heterogeneous (photo)catalysts. </a><a></a><a>By following prototype of enzymes, making all catalytic sites of accessible via homogeneous reactions is a promising approach toward maximizing CN activity, but hindered due to </a><a></a><a>the poor insolubility of CN</a>. Herein, we report the dissolution of CN in environment-friendly methane sulfonic acid and the homogeneous photocatalysis driven by CN for the first time with the activity boosted up to 10-times, comparing to the heterogeneous counterparts. Moreover, facile recycling and reusability, the <a>hallmark</a> of heterogeneous catalysts, were kept for the homogeneous CN photocatalyst via reversible precipitation using poor solvents. It opens new vista of CN in homogeneous catalysis and offers a successful example of polymeric catalysts in bridging gaps of homo/heterogeneous catalysis.

scholarly journals A Combined Computational and Experimental Study of Methane Activation during Oxidative Coupling of Methane (OCM) by Surface Metal Oxide Catalysts

2021 ◽  
Author(s):  
Daniyal Kiani ◽  
Sagar Sourav ◽  
Jonas Baltrusaitis ◽  
Israel E Wachs
Keyword(s):  
Experimental Study ◽  
Metal Oxide ◽  
Oxidative Coupling ◽  
Active Sites ◽  
Computational Models ◽  
Oxidative Coupling Of Methane ◽  
Catalytic Active Sites ◽  
Surface Metal ◽  
Heterolytic Dissociation ◽  
First Time

The experimentally validated computational models developed herein, for the first time, show that Mn-promotion does not enhance the activity of the surface Na2WO4 catalytic active sites for CH4 heterolytic dissociation...

scholarly journals Second-Generation Manganese(III) Porphyrins Bearing 3,5-Dichloropyridyl Units: Innovative Homogeneous and Heterogeneous Catalysts for the Epoxidation of Alkenes

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 967 ◽  
Author(s):  
Neves ◽  
Rebelo ◽  
Faustino ◽  
Neves ◽  
Simões
Keyword(s):  
Heterogeneous Catalysts ◽  
Second Generation ◽  
Supported Catalyst ◽  
Catalytic Efficiency ◽  
Major Product ◽  
Aqueous Hydrogen Peroxide ◽  
Tert Butyl Hydroperoxide ◽  
Merrifield Resin ◽  
Catalytic Cycles ◽  
First Time

The synthesis, characterisation and homogeneous catalytic oxidation results of two manganese(III) porphyrins of the so-called second-generation of metalloporphyrin catalysts, containing one or four 3,5-dichloropyridyl substituents at the meso positions are reported for the first time. The catalytic efficiency of these novel manganese(III) porphyrins was evaluated in the oxidation of cyclooctene and styrene using aqueous hydrogen peroxide as the oxidant, under homogeneous conditions. High conversions were obtained in the presence of both catalysts, obtaining the corresponding epoxide as the major product. The asymmetric metalloporphyrin, chloro[5,10,15-tris(2,6-dichlorophenyl)-20-(3,5-dichloropyridin-4-yl)porphyrinate]manganese(III), CAT-4, evidences a similar activity to that obtained with the well-known and highly efficient second-generation metalloporphyrin catalyst, chloro[5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrinate]manganese(III), CAT-2. CAT-4 was covalently attached onto Merrifield resin and 3-bromopropylsilica supports. The solid materials obtained were characterized by several techniques including diffuse reflectance, UV—VIS spectrophotometry, SEM and XPS. The catalytic results for the oxidation of cyclooctene and styrene using the immobilized catalysts are also presented. The Merrifield-supported catalyst showed to be very efficient, leading to five catalytic cycles in the oxidation of cyclooctene, using tert-butyl hydroperoxide as the oxidant.

scholarly journals Size-dependent electron transfer from atomically defined nanographenes to metal oxide nanoparticles

Nanoscale ◽  
2020 ◽  
Vol 12 (30) ◽  
pp. 16046-16052
Author(s):  
Peng Han ◽  
Xuelin Yao ◽  
Klaus Müllen ◽  
Akimitsu Narita ◽  
Mischa Bonn ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Metal Oxide ◽  
Metal Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Oxide Electrode ◽  
Size Dependent ◽  
Mesoporous Oxide ◽  
First Time

We analyze for the first time size-dependent electron transfer from atomically precise nanographenes to a mesoporous oxide electrode.

scholarly journals Inkjet-Printed Top-Gate Thin-Film Transistors Based on InGaSnO Semiconductor Layer with Improved Etching Resistance

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 425 ◽  
Author(s):  
Siting Chen ◽  
Yuzhi Li ◽  
Yilong Lin ◽  
Penghui He ◽  
Teng Long ◽  
...  
Keyword(s):  
Thin Film ◽  
Metal Oxide ◽  
Dielectric Layer ◽  
Thin Film Transistors ◽  
Gate Dielectric ◽  
Acid Resistance ◽  
Semiconductor Layer ◽  
Sn Doping ◽  
First Time

Inkjet-printed top-gate metal oxide (MO) thin-film transistors (TFTs) with InGaSnO semiconductor layer and carbon-free aqueous gate dielectric ink are demonstrated. It is found that the InGaO semiconductor layer without Sn doping is seriously damaged after printing aqueous gate dielectric ink onto it. By doping Sn into InGaO, the acid resistance is enhanced. As a result, the printed InGaSnO semiconductor layer is almost not affected during printing the following gate dielectric layer. The TFTs based on the InGaSnO semiconductor layer exhibit higher mobility, less hysteresis, and better stability compared to those based on InGaO semiconductor layer. To the best of our knowledge, it is for the first time to investigate the interface chemical corrosivity of inkjet-printed MO-TFTs. It paves a way to overcome the solvent etching problems for the printed TFTs.

Modelling of Multi-Ion-Beam Reactive Cosputtering for Metal Oxide Thin Films

1994 ◽  
Vol 354 ◽  
Author(s):  
D. Q. Xiao ◽  
J. G. Zhu ◽  
Z. H. Qian ◽  
W. B. Peng ◽  
L. F. Wei ◽  
...  
Keyword(s):  
Thin Films ◽  
Numerical Simulation ◽  
Metal Oxide ◽  
Ion Beam ◽  
Substrate Surface ◽  
Oxide Thin Films ◽  
Metal Oxide Thin Films ◽  
A New Technique ◽  
Computer Numerical Simulation ◽  
First Time

AbstractVery recently a new technique named multi-ion-bram reactive cosputtering(MIBRECS) was developed for preparing multi-component metal oxide thin films. Epitaxial or highly oriented (Pb,La) TiO3 thin films sputtered from pure metals of lead, titanium and lathanium were deposited by using this technique. In order to consummate the technique and to study the mechanism of reactive cosputtering, a general model of multi-ion-beam reactive cosputter-ing was proposed for the first time based on the well-known gas kinetics under stable sputtering circumstances, and a computer numerical simulation of the model was carried out with the parameters adopted in our experiments. The relationships among the sputtering ratioes of the targets, and the coverage ratioes of simple substances and oxides of the target metals on substrate surface with the total reactive gas flux and the densities of the sputtering ion beam were obtained respectively, and the hysteresis effect of the characteristic of reactive sputtering and the interactions during multi-ion-beam reactive cosputtering processes were also obtained. The numerical simulation results are at least qualitively in agreement with the experiments.

scholarly journals Designing Heterogeneous Catalysts for Renewable Catalysis Applications Using Metal Oxide Deposition

2019 ◽  
Vol 73 (9) ◽  
pp. 698-706
Author(s):  
Yuan-Peng Du ◽  
Jeremy S. Luterbacher
Keyword(s):  
Heterogeneous Catalysis ◽  
Metal Oxide ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
High Surface ◽  
Catalyst Stability ◽  
Synthetic Control ◽  
High Oxygen Content ◽  
Oxide Deposition

Heterogeneous catalysis has long been a workhorse for the chemical industry and will likely play a key role in the emerging area of renewable chemistry. However, renewable molecule streams pose unique challenges for heterogeneous catalysis due to their high oxygen content, frequent low volatility and the near constant presence of water. These constraints can often lead to the need for catalyst operation in harsh liquid phase conditions, which has compounded traditional catalyst deactivation issues. Oxygenated molecules are also frequently more reactive than petroleum-derived molecules, which creates a need for highly selective catalysts. Synthetic control over the nanostructured environment of catalytic active sites could facilitate the creation of both more stable and selective catalysts. In this review, we discuss the use of metal oxide deposition as an emerging strategy that can be used to synthesize and/or modify heterogeneous catalysts to introduce tailored nanostructures. Several important applications are reviewed, including the synthesis of high surface area mesoporous metal oxides, the enhancement of catalyst stability, and the improvement of catalyst selectivity.

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