Influence of the backbone of N5-pentadentate ligands on the catalytic performance of Ni(ii) complexes for electrochemical water oxidation in neutral aqueous solutions

2018 ◽  
Vol 54 (65) ◽  
pp. 9019-9022 ◽  
Author(s):  
Junyu Shen ◽  
Mei Wang ◽  
Tianhao He ◽  
Jian Jiang ◽  
Maowei Hu
Keyword(s):  
Aqueous Solutions ◽  
Water Oxidation ◽  
Nickel Catalysts ◽  
Catalytic Performance ◽  
Positive Influence ◽  
Chelating Ligands ◽  
Pentadentate Ligands

A positive influence of the rigid backbone of N5-chelating ligands was demonstrated on the activity of nickel catalysts for electrochemical water oxidation.

Catalytic performance of manganese-promoted nickel catalysts for the steam reforming of tar from biomass pyrolysis to synthesis gas

Fuel ◽  
2013 ◽  
Vol 103 ◽  
pp. 122-129 ◽  
Author(s):  
Mitsuru Koike ◽  
Chiaki Ishikawa ◽  
Dalin Li ◽  
Lei Wang ◽  
Yoshinao Nakagawa ◽  
...  
Keyword(s):  
Synthesis Gas ◽  
Steam Reforming ◽  
Nickel Catalysts ◽  
Catalytic Performance ◽  
Biomass Pyrolysis

scholarly journals Water-Oxidation Electrocatalysis by Manganese Oxides: Syntheses, Electrode Preparations, Electrolytes and Two Fundamental Questions

2020 ◽  
Vol 234 (5) ◽  
pp. 925-978 ◽  
Author(s):  
Jens Melder ◽  
Peter Bogdanoff ◽  
Ivelina Zaharieva ◽  
Sebastian Fiechter ◽  
Holger Dau ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Manganese Oxides ◽  
Catalyst Support ◽  
Catalytic Performance ◽  
Alkaline Solutions ◽  
Oxygen Evolving Complex ◽  
Conducting Oxides ◽  
First Choice ◽  
The Right ◽  
Number Of Equilibria

AbstractThe efficient catalysis of the four-electron oxidation of water to molecular oxygen is a central challenge for the development of devices for the production of solar fuels. This is equally true for artificial leaf-type structures and electrolyzer systems. Inspired by the oxygen evolving complex of Photosystem II, the biological catalyst for this reaction, scientists around the globe have investigated the possibility to use manganese oxides (“MnOx”) for this task. This perspective article will look at selected examples from the last about 10 years of research in this field. At first, three aspects are addressed in detail which have emerged as crucial for the development of efficient electrocatalysts for the anodic oxygen evolution reaction (OER): (1) the structure and composition of the “MnOx” is of central importance for catalytic performance and it seems that amorphous, MnIII/IV oxides with layered or tunnelled structures are especially good choices; (2) the type of support material (e.g. conducting oxides or nanostructured carbon) as well as the methods used to immobilize the MnOx catalysts on them greatly influence OER overpotentials, current densities and long-term stabilities of the electrodes and (3) when operating MnOx-based water-oxidizing anodes in electrolyzers, it has often been observed that the electrocatalytic performance is also largely dependent on the electrolyte’s composition and pH and that a number of equilibria accompany the catalytic process, resulting in “adaptive changes” of the MnOx material over time. Overall, it thus has become clear over the last years that efficient and stable water-oxidation electrolysis by manganese oxides can only be achieved if at least four parameters are optimized in combination: the oxide catalyst itself, the immobilization method, the catalyst support and last but not least the composition of the electrolyte. Furthermore, these parameters are not only important for the electrode optimization process alone but must also be considered if different electrode types are to be compared with each other or with literature values from literature. Because, as without their consideration it is almost impossible to draw the right scientific conclusions. On the other hand, it currently seems unlikely that even carefully optimized MnOx anodes will ever reach the superb OER rates observed for iridium, ruthenium or nickel-iron oxide anodes in acidic or alkaline solutions, respectively. So at the end of the article, two fundamental questions will be addressed: (1) are there technical applications where MnOx materials could actually be the first choice as OER electrocatalysts? and (2) do the results from the last decade of intensive research in this field help to solve a puzzle already formulated in 2008: “Why did nature choose manganese to make oxygen?”.

scholarly journals Ni-Based Complexes in Selective Ethylene Oligomerization Processes

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 498
Author(s):  
Giyjaz E. Bekmukhamedov ◽  
Aleksandr V. Sukhov ◽  
Aidar M. Kuchkaev ◽  
Dmitry G. Yakhvarov
Keyword(s):  
High Density Polyethylene ◽  
Petrochemical Industry ◽  
Nickel Catalysts ◽  
Catalytic Performance ◽  
Ethylene Oligomerization ◽  
Linear Low Density Polyethylene ◽  
Main Method ◽  
The World ◽  
World Demand ◽  
Alpha Olefins

Linear alpha-olefins are widely used in the petrochemical industry and the world demand for these compounds increases annually. At present, the main method for producing linear alpha-olefins is the homogeneous catalytic ethylene oligomerization. This review presents modern nickel catalysts for this process, mainly systems for obtaining of one of the most demanded oligomer—1-butene—which is used for the production of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE). The dependence of the catalytic performance on the composition and the structure of the used activated complexes, the electronic and coordination states of the nickel center was considered.

Ruthenium catalysts for water oxidation involving tetradentate polypyridine-type ligands

2015 ◽  
Vol 185 ◽  
pp. 87-104 ◽  
Author(s):  
Lianpeng Tong ◽  
Ruifa Zong ◽  
Rongwei Zhou ◽  
Nattawut Kaveevivitchai ◽  
Gang Zhang ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Catalytic Performance ◽  
Ruthenium Catalysts ◽  
Oxidation States ◽  
Coordination Geometry ◽  
Tetradentate Ligand ◽  
Catalytic Behavior ◽  
Axial Ligands ◽  
Substituted Pyridines ◽  
Equatorial Ligand

A series of RuII complexes that behave as water oxidation catalysts were prepared involving a tetradentate equatorial ligand and two 4-substituted pyridines as the axial ligands. Two of these complexes were derived from 2,9-di-(pyrid-2′-yl)-1,10-phenanthroline (dpp) and examine the effect of incorporating electron-donating amino and bulky t-butyl groups on catalytic activity. A third complex replaced the two distal pyridines with N-methylimidazoles that are more electron-donating than the pyridines of dpp and potentially stabilize higher oxidation states of the metal. The tetradentate ligand 2-(pyrid-2′-yl)-6-(1′′,10′′-phenanthrol-2′′-yl)pyridine (bpy–phen), possessing a bonding cavity similar to dpp, was also prepared. The RuII complex of this ligand does not have two rotatable pyridines in the equatorial plane and thus shows different flexibility from the [Ru(dpp)] complexes. All the complexes showed activity towards water oxidation. Investigation of their catalytic behavior and electrochemical properties suggests that they may follow the same catalytic pathway as the prototype [Ru(dpp)pic2]2+ involving a seven-coordinated [RuIV(O)] intermediate. The influence of coordination geometry on catalytic performance is analyzed and discussed.

Influence of phase composition and particle size of atomised Ni–Al alloy samples on the catalytic performance of Raney-type nickel catalysts

2009 ◽  
Vol 356 (2) ◽  
pp. 154-161 ◽  
Author(s):  
F. Devred ◽  
A.H. Gieske ◽  
N. Adkins ◽  
U. Dahlborg ◽  
C.M. Bao ◽  
...  
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Nickel Catalysts ◽  
Catalytic Performance ◽  
Al Alloy ◽  
Type Nickel

Intensified-Fenton process for the treatment of phenol aqueous solutions

2014 ◽  
Vol 71 (3) ◽  
pp. 359-365 ◽  
Author(s):  
M. Isabel Pariente ◽  
Raúl Molina ◽  
Juan Antonio Melero ◽  
Juan Ángel Botas ◽  
Fernando Martínez
Keyword(s):  
Hydrogen Peroxide ◽  
Aqueous Solutions ◽  
Heterogeneous Catalyst ◽  
Reaction Temperature ◽  
Catalytic Performance ◽  
Fenton Process ◽  
Iron Species ◽  
Iron Extraction ◽  
Dissolved Iron ◽  
Iron Leaching

An intensified-Fenton process for the treatment of phenol aqueous solutions has been studied as a continuous catalytic wet hydrogen peroxide oxidation system. This process consists of coupling the catalytic activity of a heterogeneous Fenton-like catalyst with the homogeneous contribution of its dissolved iron species. Agglomerated mesoporous SBA-15 silica-supported iron oxide (Fe2O3/SBA-15) material was used as heterogeneous catalyst. The influence of the reaction temperature and the initial hydrogen peroxide dosages was studied in order to minimize the operation cost of the process. The catalytic performance of the process was assessed in terms of total organic carbon (TOC) and hydrogen peroxide conversions. Likewise, the stability of the solid Fenton-like catalyst was also evaluated in terms of the dissolved iron species. The increase of the reaction temperature enhanced the TOC conversion and reduced the iron leaching from the heterogeneous catalyst. These results were related to the degradation of oxalic acid as responsible for iron extraction by formation of soluble stable iron complexes into the aqueous medium. Finally, the use of a moderate hydrogen peroxide concentration (2.6 g/L) and milder temperatures (80–120 °C) has led to remarkable results of TOC and phenol reductions as well as oxidant efficiency through the intensified-Fenton process.

Understanding Structure-Dependent Catalytic Performance of Nickel Selenides for Electrochemical Water Oxidation

ACS Catalysis ◽  
2016 ◽  
Vol 7 (1) ◽  
pp. 310-315 ◽  
Author(s):  
Kun Xu ◽  
Hui Ding ◽  
Haifeng Lv ◽  
Shi Tao ◽  
Pengzuo Chen ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Catalytic Performance

Synthesis and oxygen evolution reaction (OER) catalytic performance of Ni2−xRuxP nanocrystals: enhancing activity by dilution of the noble metal

2017 ◽  
Vol 5 (33) ◽  
pp. 17609-17618 ◽  
Author(s):  
D. Ruchira Liyanage ◽  
Da Li ◽  
Quintin B. Cheek ◽  
Habib Baydoun ◽  
Stephanie L. Brock
Keyword(s):  
Oxygen Evolution ◽  
Noble Metal ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Catalytic Performance ◽  
Redox Behavior

Incorporation of Ru into Ni2P nanoparticles moderates the redox behavior of Ni and lowers the kinetic barrier for water oxidation.

scholarly journals Acetic acid hydroconversion over mono- and bimetallic indium doped catalysts supported on alumina and silicas of various textures

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
György Onyestyák ◽  
Szabolcs Harnos ◽  
Cecília Andrea Badari ◽  
Eszter Drotár ◽  
Szilvia Klébert ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Fixed Bed ◽  
Textural Properties ◽  
Nickel Catalysts ◽  
Catalytic Performance ◽  
Hydrogen Flow ◽  
Silica Supports ◽  
Ordered Mesoporous ◽  
Flow Through ◽  
Selective Addition

AbstractConsecutive hydroconversion of acetic acid (AA) to ethanol was compared over monometallic and novel bimetallic (containing In as guest metal) catalysts on alumina and silica supports (inter alia highly ordered SBA-15) of different porosity and pore structure. The transformation was studied in a fixed bed, flow-through reactor in the temperature range of 220–380°C using hydrogen flow at 21 bar total pressure. AA hydroconversion activity of Cu and Pt catalysts and the yield of selectively produced alcohol were increased drastically by applying SBA-15 as highly ordered, mesoporous silica support instead of alumina. The most active nickel catalysts do not allow the selective addition of hydrogen to carbon-oxygen bonds independently of supports producing mainly CH4; however, indium doping can completely eliminate the hydrodecarbonylation activity as found in earlier studies. The textural properties of studied silica supports of various textures such as SBA-15, CAB-O-SIL, and Grace Sylobead have a profound impact on the catalytic performance of Ni and Ni2In particles.

The effect of the trans axial ligand of cobalt corroles on water oxidation activity in neutral aqueous solutions

2017 ◽  
Vol 19 (15) ◽  
pp. 9755-9761 ◽  
Author(s):  
Liang Xu ◽  
Haitao Lei ◽  
Zongyao Zhang ◽  
Zhen Yao ◽  
Jianfeng Li ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Water Oxidation ◽  
Axial Ligand ◽  
Oxidation Activity ◽  
Axial Ligands

Co corroles containing electron-donating trans axial ligands are more active than those containing electron-withdrawing trans axial ligands in catalyzing water oxidation.

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