scholarly journals Iridium Complex Catalyzed Hydrogen Production from Glucose and Various Monosaccharides

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 891
Author(s):  
Ken-ichi Fujita ◽  
Takayoshi Inoue ◽  
Toshiki Tanaka ◽  
Jaeyoung Jeong ◽  
Shohichi Furukawa ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Catalytic System ◽  
Catalytic Reaction ◽  
Hydrogen Gas ◽  
Water Soluble ◽  
Starting Material ◽  
Iridium Complex ◽  
Production Of Hydrogen ◽  
Bipyridine Ligand

A new catalytic system has been developed for hydrogen production from various monosaccharides, mainly glucose, as a starting material under reflux conditions in water in the presence of a water-soluble dicationic iridium complex bearing a functional bipyridine ligand. For example, the reaction of D-glucose in water under reflux for 20 h in the presence of [Cp*Ir(6,6′-dihydroxy-2,2′-bipyridine)(H2O)][OTf]2 (1.0 mol %) (Cp*: pentamethylcyclopentadienyl, OTf: trifluoromethanesulfonate) resulted in the production of hydrogen gas in 95% yield. In the present catalytic reaction, it was experimentally suggested that dehydrogenation of the alcoholic moiety at 1-position of glucose proceeded.

Reactive Molecular Dynamics Simulations, Data Analytics and Visualization

2015 ◽  
Vol 1756 ◽  
Author(s):  
Priya Vashishta ◽  
Rajiv K. Kalia ◽  
Aiichiro Nakano ◽  
Ying Li ◽  
Ken-ichi Nomura ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Production ◽  
Density Functional ◽  
Silica Surface ◽  
Hydrogen Gas ◽  
Divide And Conquer ◽  
List Type ◽  
Reactive Molecular Dynamics ◽  
Production Of Hydrogen ◽  
Blue Gene

ABSTRACTMultimillion-atom reactive molecular dynamics (RMD) and large quantum molecular dynamics (QMD) simulations are used to investigate structural and dynamical correlations under highly nonequilibrium conditions and reactive processes in nanostructured materials under extreme conditions. This paper discusses four simulations:1.RMD simulations of heated aluminum nanoparticles have been performed to study the fast oxidation reaction processes of the core (aluminum)-shell (alumina) nanoparticles and small complexes.2.Cavitation bubbles readily occur in fluids subjected to rapid changes in pressure. We have used billion-atom RMD simulations on a 163,840-processor Blue Gene/P supercomputer to investigate chemical and mechanical damages caused by shock-induced collapse of nanobubbles in water near silica surface. Collapse of an empty nanobubble generates high-speed nanojet, resulting in the formation of a pit on the surface. The gas-filled bubbles undergo partial collapse and consequently the damage on the silica surface is mitigated.3.Our QMD simulation reveals rapid hydrogen production from water by an Al superatom. We have found a low activation-barrier mechanism, in which a pair of Lewis acid and base sites on the Aln surface preferentially catalyzes hydrogen production.4.We have introduced an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large QMD simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786,432 cores for a 50.3 million-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16,661 atoms was performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles.

scholarly journals Photoelectrochemical Water Splitting Reaction System Based on Metal-Organic Halide Perovskites

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 210 ◽  
Author(s):  
Dohun Kim ◽  
Dong-Kyu Lee ◽  
Seong Min Kim ◽  
Woosung Park ◽  
Uk Sim
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Fossil Fuels ◽  
Reaction System ◽  
Hydrogen Gas ◽  
Production Environment ◽  
Organic Halide ◽  
Highly Active ◽  
Production Of Hydrogen ◽  
Metal Organic

In the development of hydrogen-based technology, a key challenge is the sustainable production of hydrogen in terms of energy consumption and environmental aspects. However, existing methods mainly rely on fossil fuels due to their cost efficiency, and as such, it is difficult to be completely independent of carbon-based technology. Electrochemical hydrogen production is essential, since it has shown the successful generation of hydrogen gas of high purity. Similarly, the photoelectrochemical (PEC) method is also appealing, as this method exhibits highly active and stable water splitting with the help of solar energy. In this article, we review recent developments in PEC water splitting, particularly those using metal-organic halide perovskite materials. We discuss the exceptional optical and electrical characteristics which often dictate PEC performance. We further extend our discussion to the material limit of perovskite under a hydrogen production environment, i.e., that PEC reactions often degrade the contact between the electrode and the electrolyte. Finally, we introduce recent improvements in the stability of a perovskite-based PEC device.

I-V Characteristic and Performance of Three Electrode Alkaline Electrolyzer

2021 ◽  
Author(s):  
Diwakar Kafle ◽  
Sushil Dumre ◽  
Saroj Tripathi ◽  
Shankar Shrestha
Keyword(s):  
Hydrogen Production ◽  
Electricity Consumption ◽  
Cost Effective ◽  
Hydrogen Gas ◽  
Voltage Source ◽  
Promising Technique ◽  
Environment Friendly ◽  
Main Challenge ◽  
Production Of Hydrogen ◽  
And Performance

Abstract Hydrogen production by electrolysis of water is seen as a promising technique as it is environment friendly and it can use renewable energy source for the production of hydrogen gas. However, this technology has less than 4% contribution to the production of commercial hydrogen in the market. This is due to the high electricity consumption of the water splitting reaction. The main challenge to make this technology efficient and economically viable is to develop cost effective and highly efficient electrolyzer. Here we have developed a three electrode electrolyzer in which an extra electrode is inserted between conventional electrodes: cathode and anode. This novel electrolyzer utilizes an extra voltage source which reduces the overpotential and increases the anode current of the cell, which is responsible for the hydrogen production. Furthermore, we observed that, the operating resistance of the cell decreases under the application of the new voltage source. Our results demonstrate that the introduction of third electrode improves the performance of electrolysis by consuming less power as compared to the traditional or conventional two electrode electrolyzer system.

scholarly journals Dehydrogenative Transformation of Alcoholic Substrates in Aqueous Media Catalyzed by an Iridium Complex Having a Functional Ligand with α-Hydroxypyridine and 4,5-Dihydro-1H-imidazol-2-yl Moieties

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 312 ◽  
Author(s):  
Masato Yoshida ◽  
Han Wang ◽  
Takuya Shimbayashi ◽  
Ken-ichi Fujita
Keyword(s):  
Catalytic System ◽  
Aqueous Media ◽  
Catalytic Performance ◽  
Water Soluble ◽  
Iridium Complex ◽  
Similar Reaction ◽  
Reaction Conditions ◽  
System A ◽  
Iridium Catalyst ◽  
Oxidation Of Alcohols

A new catalytic system that employs water as an environmentally friendly solvent for the dehydrogenative oxidation of alcohols and lactonization of diols has been developed. In this catalytic system, a water-soluble dicationic iridium complex having a functional ligand that comprises α-hydroxypyridine and 4,5-dihydro-1H-imidazol-2-yl moieties exhibits high catalytic performance. For example, the catalytic dehydrogenative oxidation of 1-phenylethanol in the presence of 0.25 mol % of the iridium catalyst and base under reflux in water proceeded to give acetophenone in 92% yield. Additionally, under similar reaction conditions, the iridium-catalyzed dehydrogenative lactonization of 1,2-benzenedimethanol gave phthalide in 98% yield.

Metabolic engineering for enhanced hydrogen production: a review

2013 ◽  
Vol 59 (2) ◽  
pp. 59-78 ◽  
Author(s):  
Yogesh Goyal ◽  
Manish Kumar ◽  
Kalyan Gayen
Keyword(s):  
Metabolic Engineering ◽  
Hydrogen Production ◽  
Hydrogen Gas ◽  
Published Data ◽  
Dual Systems ◽  
Wide Range ◽  
Production Of Hydrogen ◽  
Different Strains ◽  
High Yields ◽  
Associated Species

Hydrogen gas exhibits potential as a sustainable fuel for the future. Therefore, many attempts have been made with the aim of producing high yields of hydrogen gas through renewable biological routes. Engineering of strains to enhance the production of hydrogen gas has been an active area of research for the past 2 decades. This includes overexpression of hydrogen-producing genes (native and heterologous), knockout of competitive pathways, creation of a new productive pathway, and creation of dual systems. Interestingly, genetic mutations in 2 different strains of the same species may not yield similar results. Similarly, 2 different studies on hydrogen productivities may differ largely for the same mutation and on the same species. Consequently, here we analyzed the effect of various genetic modifications on several species, considering a wide range of published data on hydrogen biosynthesis. This article includes a comprehensive metabolic engineering analysis of hydrogen-producing organisms, namely Escherichia coli, Clostridium, and Enterobacter species, and in addition, a short discussion on thermophilic and halophilic organisms. Also, apart from single-culture utilization, dual systems of various organisms and associated developments have been discussed, which are considered potential future targets for economical hydrogen production. Additionally, an indirect contribution towards hydrogen production has been reviewed for associated species.

Design of multicomponent photocatalysts for hydrogen production under visible light using water-soluble titanate nanodisks

Nanoscale ◽  
2014 ◽  
Vol 6 (9) ◽  
pp. 4819-4829 ◽  
Author(s):  
Cao-Thang Dinh ◽  
Minh-Hao Pham ◽  
Yongbeom Seo ◽  
Freddy Kleitz ◽  
Trong-On Do
Keyword(s):  
Hydrogen Production ◽  
Visible Light ◽  
Catalytic Reaction ◽  
Light Absorption ◽  
Charge Separation ◽  
Water Soluble ◽  
Visible Light Absorption ◽  
Highly Efficient ◽  
Main Factors

Water-soluble multicomponent photocatalysts highly efficient for H2 generation under visible light are designed in such a way to simultaneously enhance the three main factors of photocatalysis, i.e. visible light absorption, charge separation, and surface catalytic reaction.

Research Progress of Food Waste Fermentation for Bio-Hydrogen Production

2012 ◽  
Vol 550-553 ◽  
pp. 569-573
Author(s):  
Xiao Fang Yue ◽  
Hong Yuan Sun ◽  
Xu Xin Zhao ◽  
Li Qing Zhao
Keyword(s):  
Hydrogen Production ◽  
Food Waste ◽  
Waste Treatment ◽  
Clean Energy ◽  
Hydrogen Gas ◽  
Research Progress ◽  
Fermentative Hydrogen Production ◽  
Production Of Hydrogen ◽  
Fermentative Hydrogen ◽  
Clean Energy Source

Hydrogen is a valuable gas as a clean energy source and as feedstock for some industries. Therefore, demand on hydrogen production has increased considerably in recent years. Food waste is an important part of urban living garbage,which is full of organic matter and easy to be degraded. So, biological production of hydrogen gas from food waste fermentation has significant advantages for providing inexpensive and clean energy generation to help meet the needs of carbon emission reduction with simultaneous waste treatment. This article reviews the following aspects: mechanism of fermentative hydrogen production by bacteria, and factors influencing fermentative bio-hydrogen production. In addition,the challenges and prospects of bio- hydrogen production are also reviewed.

scholarly journals Investigation of Hydrogen Production by using Zinc Coated Platinum Electrode in Phosphate Solutions

2019 ◽  
Vol 7 (1) ◽  
pp. 16-24
Author(s):  
Mustafa Kemal Sangun ◽  
Guray Kilincceker
Keyword(s):  
Hydrogen Production ◽  
Platinum Electrode ◽  
Electrochemical Impedance ◽  
Hydrogen Gas ◽  
Solution Ph ◽  
Pt Electrode ◽  
X Ray ◽  
Production Of Hydrogen ◽  
Phosphate Solutions ◽  
Scanning Electron

In this study, the hydrogen gas producing was investigated at 298 K with zinc coated platinum (Pt-Zn) electrode in 0.1 M NaH2PO4 solution (pH=12.3). Electrolysis, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques were used for the production of hydrogen gas. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray fluorescence (XRF) were used for the surface analysis of the electrodes. A practical electrocatalytic experiment was designed to examine of hydrogen production by using a Zn plated Pt electrode and the efficiency of the hydrogen gas increased by 66.66% on the surface of the zinc coated platinum electrode.

scholarly journals A Review on Production of Hydrogen from Renewable Sources and Applications for Fuel Cell Vehicles

2018 ◽  
Vol 1 (2) ◽  
pp. 63-68 ◽  
Author(s):  
Dedi Rohendi ◽  
Dea Radestia Rahmah ◽  
Dwi Hawa Yulianti ◽  
Icha Amelia ◽  
Nyimas Febrika Sya'baniah ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Raw Materials ◽  
Biomass Conversion ◽  
Hydrogen Gas ◽  
High Mass ◽  
Fuel Cell Vehicles ◽  
Renewable Sources ◽  
Renewable Raw Materials ◽  
Production Methods ◽  
Production Of Hydrogen

Hydrogen gas is an energy carrier that has many advantages, including energy density for high mass and environmentally friendly. Hydrogen can be produced from various sources by numerous methods. Hydrogen production from renewable sources is interesting, due to the sustainable and inexpensive supply of the raw materials. Among the sources of renewable raw materials for hydrogen production are water and biomass with various production methods. It consists of the electrolysis of water with acidic and basic conditions, as well as thermochemical and biochemical biomass conversion.

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