CO 2 conversion through combined steam and CO 2 reforming of methane reactions over Ni and Co catalysts

2020 ◽  
Vol 99 (1) ◽  
pp. 153-165
Author(s):  
Mohsen Shakouri ◽  
Yongfeng Hu ◽  
Rick Lehoux ◽  
Hui Wang
Keyword(s):  
Co Catalysts ◽  
Methane Reactions

Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols

2019 ◽  
Author(s):  
Ke-Yin Ye ◽  
Terry McCallum ◽  
Song Lin
Keyword(s):  
Ring Opening ◽  
High Reactivity ◽  
Hydrogen Atom Transfer ◽  
Organic Radicals ◽  
Epoxide Ring ◽  
Allylic Alcohols ◽  
Epoxide Ring Opening ◽  
Bond Forming ◽  
Co Catalysts ◽  
The Rich

Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton-transfer/electron-transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.<br>

Superior co-catalysis by bimetallic nanostructure for TiO2 photocatalysis

2020 ◽  
Vol 01 ◽  
Author(s):  
Bonamali Pal ◽  
Anila Monga ◽  
Aadil Bathla
Keyword(s):  
Visible Light ◽  
Catalytic Performance ◽  
Transition Metal Catalysts ◽  
Core Shell ◽  
Structural Morphology ◽  
Tio2 Photocatalysis ◽  
Co Catalysts ◽  
Bimetallic Nanocomposites ◽  
Bimetallic Nanostructure ◽  
Bimetallic Nanostructures

Background:: Bimetallic nanocomposites have currently gained significant importance for enhanced catalytic applications relative to monometallic analogues. The synergistic interactions modified electronic and optical properties in the bimetallic (M1@M2) structural morphology e.g., core-shell /alloy nanostructures resulted in a better co-catalytic performance for TiO2 photocatalysis. Objective:: Hence, this article discusses the preparation, characterization, and co-catalytic activity of different bimetallic nanostructures namely, Cu@Zn, Pd@Au, Au@Ag, and Ag@Cu, etc. Method:: These bimetallic co-catalysts deposited on TiO2 possess the ability to absorb visible light due to surface plasmonic absorption and are also expected to display the new properties due to synergy between two distinct metals. As a result, they reveal the highest level of activity than the monometal deposited TiO2. Result:: Their optical absorption, emission, charge carrier dynamics, and surface structural morphology are explained for the improved photocatalytic activity of M1@M2 loaded TiO2 for the hydrogenation of certain organic compounds e.g., quinoline, crotonaldehyde, and 1,3-dinitrobenzene, etc. under UV/ visible light irradiation. Conclusion:: It revealed that the use of bimetallic core@shell co-catalyst for hydrogenation of important industrial organics by M1@M2-TiO2 nanocomposite demonstrates beneficial reactivity in many instances relative to conventional transition metal catalysts.

A review of sustainable lignocellulose biorefining applying (natural) deep eutectic solvents (DESs) for separations, catalysis and enzymatic biotransformation processes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ana Bjelić ◽  
Brigita Hočevar ◽  
Miha Grilc ◽  
Uroš Novak ◽  
Blaž Likozar
Keyword(s):  
Special Section ◽  
Cost Effective ◽  
Deep Eutectic Solvents ◽  
Reaction Conditions ◽  
Co Catalysts ◽  
Biomass Fractionation ◽  
Functional Step ◽  
Natural Deep Eutectic Solvents ◽  
Economic Need ◽  
Molecular Compounds

AbstractConventional biorefinery processes are complex, engineered and energy-intensive, where biomass fractionation, a key functional step for the production of biomass-derived chemical substances, demands industrial organic solvents and harsh, environmentally harmful reaction conditions. There is a timely, clear and unmet economic need for a systematic, robust and affordable conversion method technology to become greener, sustainable and cost-effective. In this perspective, deep eutectic solvents (DESs) have been envisaged as the most advanced novel polar liquids that are entirely made of natural, molecular compounds that are capable of an association via hydrogen bonding interactions. DES has quickly emerged in various application functions thanks to a formulations’ simple preparation. These molecules themselves are biobased, renewable, biodegradable and eco-friendly. The present experimental review is providing the state of the art topical overview of trends regarding the employment of DESs in investigated biorefinery-related techniques. This review covers DESs for lignocellulosic component isolation, applications as (co)catalysts and their functionality range in biocatalysis. Furthermore, a special section of the DESs recyclability is included. For DESs to unlock numerous new (reactive) possibilities in future biorefineries, the critical estimation of its complexity in the reaction, separation, or fractionation medium should be addressed more in future studies.

scholarly journals Microwaves as “Co-Catalysts” or as Substitute for Catalysts in Organophosphorus Chemistry

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1196
Author(s):  
György Keglevich
Keyword(s):  
Coupling Reaction ◽  
Diels Alder ◽  
Typical Case ◽  
Conventional Heating ◽  
Phosphine Oxides ◽  
Phosphonic Acids ◽  
Co Catalysts ◽  
Mw Irradiation ◽  
Organophosphorus Chemistry ◽  
Hydrolysis Of

The purpose of this review is to summarize the importance of microwave (MW) irradiation as a kind of catalyst in organophosphorus chemistry. Slow or reluctant reactions, such as the Diels-Alder cycloaddition or an inverse-Wittig type reaction, may be performed efficiently under MW irradiation. The direct esterification of phosphinic and phosphonic acids, which is practically impossible on conventional heating, may be realized under MW conditions. Ionic liquid additives may promote further esterifications. The opposite reaction, the hydrolysis of P-esters, has also relevance among the MW-assisted transformations. A typical case is when the catalysts are substituted by MWs, which is exemplified by the reduction of phosphine oxides, and by the Kabachnik–Fields condensation affording α-aminophosphonic derivatives. Finally, the Hirao P–C coupling reaction may serve as an example, when the catalyst may be simplified under MW conditions. All of the examples discussed fulfill the expectations of green chemistry.

scholarly journals Preparation and High-Throughput Testing of TiO2-Supported Co Catalysts for Fischer‒Tropsch Synthesis

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 352
Author(s):  
Christian Schulz ◽  
Peter Kolb ◽  
Dennis Krupp ◽  
Lars Ritter ◽  
Alfred Haas ◽  
...  
Keyword(s):  
High Throughput ◽  
Anatase Phase ◽  
Rutile Phase ◽  
Tropsch Synthesis ◽  
Performance Tests ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Co Catalysts ◽  
Impregnation Technique ◽  
Co Conversion

A series of Co/TiO2 catalysts was tested in a parameters field study for Fischer‒Tropsch synthesis (FTS). All catalysts were prepared by the conventional impregnation technique to obtain an industrially relevant Co content of 10 wt % or 20 wt %, respectively. In summary, 10 different TiO2 of pure anatase phase, pure rutile phase, as well as mixed rutile and anatase phase were used as supports. Performance tests were conducted with a 32-fold high-throughput setup for accelerated catalyst benchmarking; thus, 48 experiments were completed within five weeks in a relevant operation parameters field (170 °C to 233.5 °C, H2/CO ratio 1 to 2.5, and 20 bar(g)). The most promising catalyst showed a CH4 selectivity of 5.3% at a relevant CO conversion of 60% and a C5+ productivity of 2.1 gC5+/(gCo h) at 207.5 °C. These TiO2-based materials were clearly differentiated with respect to the application as supports in Co-catalyzed FTS catalysis. The most prospective candidates are available for further FTS optimization at a commercial scale.

scholarly journals Ru-M (M = Fe or Co) Catalysts with high Ru surface concentration for Fischer-Tropsch synthesis

Fuel ◽  
2021 ◽  
Vol 293 ◽  
pp. 120435
Author(s):  
Dalia Liuzzi ◽  
Francisco J. Pérez-Alonso ◽  
Sergio Rojas
Keyword(s):  
Surface Concentration ◽  
Tropsch Synthesis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Co Catalysts

scholarly journals The Effect of Iron Impurities on Transition Metal Catalysts for the Oxygen Evolution Reaction in Alkaline Environment: Activity Mediators or Active Sites?

2020 ◽  
Author(s):  
Ioannis Spanos ◽  
Justus Masa ◽  
Aleksandar Zeradjanin ◽  
Robert Schlögl
Keyword(s):  
Transition Metal ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Water Electrolysis ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Alkaline Water Electrolysis ◽  
Co Catalysts ◽  
Model Transition

AbstractThere is an ongoing debate on elucidating the actual role of Fe impurities in alkaline water electrolysis, acting either as reactivity mediators or as co-catalysts through synergistic interaction with the main catalyst material. This perspective summarizes the most prominent oxygen evolution reaction (OER) mechanisms mostly for Ni-based oxides as model transition metal catalysts and highlights the effect of Fe incorporation on the catalyst surface in the form of impurities originating from the electrolyte or co-precipitated in the catalyst lattice, in modulating the OER reaction kinetics, mechanism and stability. Graphic Abstract

Enhanced photocatalytic H2 evolution over In2S3 via decoration with GO and Fe2P co-catalysts

2021 ◽  
Author(s):  
Xue Li ◽  
Xianjun Lyu ◽  
Xiaohan Zhao ◽  
Yan Zhang ◽  
Stephen Nyabire Akanyange ◽  
...  
Keyword(s):  
H2 Evolution ◽  
Co Catalysts ◽  
Photocatalytic H2 Evolution

scholarly journals The effect of nanoparticulate PdO co-catalysts on the faradaic and light conversion efficiency of WO3 photoanodes for water oxidation

2021 ◽  
Author(s):  
Anna A. Wilson ◽  
Sacha Corby ◽  
Laia Francàs ◽  
James R. Durrant ◽  
Andreas Kafizas
Keyword(s):  
Conversion Efficiency ◽  
Water Oxidation ◽  
Faradaic Efficiency ◽  
Co Catalysts ◽  
Photocurrent Generation ◽  
Light Conversion Efficiency ◽  
Electron Extraction

PdO nanoparticles grown on the surface of nanostructured WO3 photoanodes dramatically increase the faradaic efficiency of water oxidation from 52% to 92%, whilst also enhancing photocurrent generation and electron extraction rates.

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