Hydrogen generation by hydrolysis of metals and hydrides for portable energy supply

2021 ◽  
pp. 15-37
Author(s):  
A. Kutsyi ◽  
◽  
A. Kytsya ◽  
V. Yartys ◽  
I. Zavaliy ◽  
...  
Keyword(s):  
Rate Constant ◽  
Energy Supply ◽  
Hydrogen Generation ◽  
National Academy Of Sciences ◽  
Hydrogen Flow ◽  
Complex Hydride ◽  
Different Types ◽  
And Performance ◽  
Catalytic Additives ◽  
Hydrolysis Of

NATO project G 5233 “Portable energy supply” was executed by 4 teams (Institute for Energy Technology, Norway and 3 Institutes of the National Academy of Sciences of Ukraine). G5233 Project was focused on the development of hydrogen fueled portable energy supply systems integrating hydrogen generation and storage units based on use of light metals, metal and complex hydride materials and portable fuel cells. The weight efficient energy supply device was developed by using these selected materials and performance-optimised NaBH4 complex hydride. Besides, various new relevant units of equipment for the samples preparation and characterization were ordered and accommodated in the participants labs and the program of training of young scientists at IFE, Norway was accomplished. Different types of materials for hydrogen generation were synthesized and characterized (activated aluminium alloys, Mg-Al alloys, MgH2 and their composites, NaBH4 with catalytic additives). The challenging objective of reaching a completeness of the hydrolysis of MgH2 was achieved; the reaction conditions were optimized and the particular focus applications integrating efficient hydrogen generation systems were identified. The mechanism and the kinetics model of the hydrolysis process of MgH2 in water solutions have been proposed which successfully describe the experimental data. In parallel with the hydrolysis reaction resulting in hydrogen generation and formation of Mg(OH)2 , the process involves passivation of the MgH2 surface by the formed Mg(OH)2 precipitate followed by its re-passivation with the rate constants of these processes being established. Increase of the concentration of MgCl2 leads to just a minor increase in the rate constant of the interaction of MgH2 with water but leads to a sharp increase of the rate constant of the repassivation of MgH2 surface. To achieve efficient hydrolysis of NaBH4 , different types of catalysts (heterogeneous on the basis of Pt and "homogeneous" - salts of Ni+2 and Co+2) were studied and optimized. Several systems were selected as candidates to provide the required hydrogen flow to operate a 30 W fuel cell over a given time exceeding 1 hour, based on a use of inexpensive and affordable hydrogen-containing materials and catalytic additives. 3 individual hydrolysis workstations (1 in Norway and 2 in Ukraine) were built, tested and optimized. The plan of the work to reach the objectives of the Project G5233 “Portable energy supply” is completely accomplished, all the milestones are successfully fulfilled and the overall goal of the Project is reached.

Activation of Acetone and Other Simple Ketones in Anaerobic Bacteria

2016 ◽  
Vol 26 (1-3) ◽  
pp. 152-164 ◽  
Author(s):  
Johann Heider ◽  
Karola Schühle ◽  
Jasmin Frey ◽  
Bernhard Schink
Keyword(s):  
Energy Supply ◽  
Anaerobic Bacteria ◽  
Aerobic Bacteria ◽  
Metabolic Intermediate ◽  
Present Evidence ◽  
Sulfate Reducing ◽  
Different Types ◽  
Subsequent Degradation ◽  
Reducing Bacteria ◽  
Hydrolysis Of

Acetone and other ketones are activated for subsequent degradation through carboxylation by many nitrate-reducing, phototrophic, and obligately aerobic bacteria. Acetone carboxylation leads to acetoacetate, which is subsequently activated to a thioester and degraded via thiolysis. Two different types of acetone carboxylases have been described, which require either 2 or 4 ATP equivalents as an energy supply for the carboxylation reaction. Both enzymes appear to combine acetone enolphosphate with carbonic phosphate to form acetoacetate. A similar but more complex enzyme is known to carboxylate the aromatic ketone acetophenone, a metabolic intermediate in anaerobic ethylbenzene metabolism in denitrifying bacteria, with simultaneous hydrolysis of 2 ATP to 2 ADP. Obligately anaerobic sulfate-reducing bacteria activate acetone to a four-carbon compound as well, but via a different process than bicarbonate- or CO<sub>2</sub>-dependent carboxylation. The present evidence indicates that either carbon monoxide or a formyl residue is used as a cosubstrate, and that the overall ATP expenditure of this pathway is substantially lower than in the known acetone carboxylase reactions.

Optimization of Mg Scraps Hydrolysis for Hydrogen Generation Using HCl: Experimental and Simulation

2019 ◽  
Author(s):  
Rokhsareh Akbarzadeh ◽  
Qusai Ibrahim ◽  
Joshua Adeniran ◽  
Peter Oviroh ◽  
Tien-Chien Jen
Keyword(s):  
Power Generation ◽  
Experimental Study ◽  
Numerical Modeling ◽  
Energy Supply ◽  
Hydrogen Generation ◽  
Clean Energy ◽  
Optimum Concentration ◽  
Influencing Parameters ◽  
Hcl Concentration ◽  
Hydrolysis Of

Abstract Worldwide concerns on environmental pollution and the need for clean energy supply have attracted researchers’ interest for power generation using technology which not only is a clean technology but also utilizes the Mg scrap waste, a part of solid waste from electronic and automobile industries. The Mg scraps have been used for the hydrogen generation via hydrolysis. In an attempt we conducted the experimental study and optimization of hydrolysis of Mg scraps waste in the presence of HCl to generate hydrogen. This work optimizes the process of using Mg scraps to produce H2, Mg(OH)2 and MgCl2. The effect of different concentration of HCl on hydrolysis was studied to find the optimum concentration for the hydrogen generation. The most influencing parameters such as acid concentration of solution was selected and studied. The kinetic behaviour was analysed to determine the effect of different HCl concentration on hydrogen generation pattern. Numerical modeling was performed considering the chemical reaction using ReaxFF. The effect of the selected parameters on the system and the hydrogen concentration were investigated to predict the performance of the hydrolysis of Mg scraps in the designed reactor. This study proposes an eco-efficient method as it utilizes the Mg waste to produce hydrogen which is an energy carrier.

ZIF-67 derived cobalt-based catalysts for hydrogen generation from the hydrolysis of alkaline sodium borohydride solution

2019 ◽  
Vol 12 (04) ◽  
pp. 1950050 ◽  
Author(s):  
Lei Wei ◽  
Hongyan Liu ◽  
Qian Wang ◽  
Wenjuan Li ◽  
Lufeng Peng
Keyword(s):  
Catalytic Activity ◽  
Sodium Borohydride ◽  
Pyrolysis Temperature ◽  
Hydrogen Generation ◽  
Low Cost ◽  
Displacement Method ◽  
Water Displacement ◽  
Catalyst Composition ◽  
And Performance ◽  
Hydrolysis Of

Cobalt-based catalysts are highly efficient and low-cost for sodium borohydride (NaBH[Formula: see text] hydrolysis to generate hydrogen. Co3O4 and carbon-supported metal Co (i.e., Co/C) catalysts were prepared by means of ZIF-67 pyrolysis. Effects of pyrolysis temperature and atmosphere on catalyst composition and performance were mainly investigated. For material analyses, a series of characterizations were carried out including FE-SEM, TEM, XRD, BET, TGA and ICP-AES. Conventional water-displacement method was employed to evaluate the catalyst performance toward NaBH4 hydrolysis. Experimental results indicated that catalytic activity of the Co3O4 was much higher than that of Co/C, and the reasons were discussed in detail.

scholarly journals Recent Advances in Applications of Co-B Catalysts in NaBH4-Based Portable Hydrogen Generators

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 268
Author(s):  
Valentina I. Simagina ◽  
Anna M. Ozerova ◽  
Oksana V. Komova ◽  
Olga V. Netskina
Keyword(s):  
Proton Exchange Membrane ◽  
Hydrogen Generation ◽  
Solid Phase ◽  
Reaction Medium ◽  
Proton Exchange ◽  
Cobalt Catalysts ◽  
Batch Reactors ◽  
Exchange Membrane ◽  
Catalytic Additives ◽  
Hydrolysis Of

This review highlights the opportunities of catalytic hydrolysis of NaBH4 with the use of inexpensive and active Co-B catalysts among the other systems of hydrogen storage and generation based on water reactive materials. This process is important for the creation of H2 generators required for the operation of portable compact power devices based on low-temperature proton exchange membrane fuel cells (LT PEM FC). Special attention is paid to the influence of the reaction medium on the formation of active state of Co-B catalysts and the problem of their deactivation in NaBH4 solution stabilized by alkali. The novelty of this review consists in the discussion of basic designs of hydrogen generators based on NaBH4 hydrolysis using cobalt catalysts and the challenges of their integration with LT PEM FC. The potential of using batch reactors in which there is no need to use aggressive alkaline NaBH4 solutions is discussed. Solid-phase compositions or pellets based on NaBH4 and cobalt-containing catalytic additives are proposed, the hydrogen generation from which starts immediately after the addition of water. The review made it possible to formulate the most acute problems, which require new sci-tech solutions.

Characteristics of Physicians Referred for a Competence Assessment: A Comparison of State Medical Board and Hospital Referred Physicians

2010 ◽  
Vol 96 (3) ◽  
pp. 8-15 ◽  
Author(s):  
Elizabeth S. Grace ◽  
Elizabeth J. Korinek ◽  
Zung V. Tran
Keyword(s):  
Clinical Competence ◽  
Competence Assessment ◽  
Average Performance ◽  
Medical Board ◽  
Key Characteristics ◽  
Different Types ◽  
Specialty Board ◽  
And Performance ◽  
State Medical Boards ◽  
State Medical Board

ABSTRACT This study compares key characteristics and performance of physicians referred to a clinical competence assessment and education program by state medical boards (boards) and hospitals. Physicians referred by boards (400) and by hospitals (102) completed a CPEP clinical competence assessment between July 2002 and June 2010. Key characteristics, self-reported specialty, and average performance rating for each group are reported and compared. Results show that, compared with hospital-referred physicians, board-referred physicians were more likely to be male (75.5% versus 88.3%), older (average age 54.1 versus 50.3 years), and less likely to be currently specialty board certified (80.4% versus 61.8%). On a scale of 1 (best) to 4 (worst), average performance was 2.62 for board referrals and 2.36 for hospital referrals. There were no significant differences between board and hospital referrals in the percentage of physicians who graduated from U.S. and Canadian medical schools. The most common specialties referred differed for boards and hospitals. Conclusion: Characteristics of physicians referred to a clinical competence program by boards and hospitals differ in important respects. The authors consider the potential reasons for these differences and whether boards and hospitals are dealing with different subsets of physicians with different types of performance problems. Further study is warranted.

An Enhanced Two Stage MMSE Equalizer for Coded FBMC/OQAM Systems

2019 ◽  
Vol 10 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Mohammad Rizk Assaf ◽  
Abdel-Nasser Assimi
Keyword(s):  
Error Propagation ◽  
Channel Model ◽  
Error Correcting Codes ◽  
Two Stage ◽  
Probability Of Error ◽  
Second Stage ◽  
Different Types ◽  
Mmse Equalizer ◽  
And Performance ◽  
Ici Cancellation

In this article, the authors investigate the enhanced two stage MMSE (TS-MMSE) equalizer in bit-interleaved coded FBMC/OQAM system which gives a tradeoff between complexity and performance, since error correcting codes limits error propagation, so this allows the equalizer to remove not only ICI but also ISI in the second stage. The proposed equalizer has shown less design complexity compared to the other MMSE equalizers. The obtained results show that the probability of error is improved where SNR gain reaches 2 dB measured at BER compared with ICI cancellation for different types of modulation schemes and ITU Vehicular B channel model. Some simulation results are provided to illustrate the effectiveness of the proposed equalizer.

scholarly journals Kinetics and Mechanistic Study of Hydrolysis of Adenosine Monophosphate Disodium Salt (AMPNa2) in Acidic and Alkaline Media

2019 ◽  
Vol 17 (1) ◽  
pp. 544-556
Author(s):  
Yoke-Leng Sim ◽  
Beljit Kaur
Keyword(s):  
Rate Constant ◽  
Adenosine Monophosphate ◽  
Disodium Salt ◽  
Second Order ◽  
Information Storage ◽  
Alkaline Media ◽  
Basic Medium ◽  
Mechanistic Study ◽  
Phosphate Ester ◽  
Hydrolysis Of

AbstractPhosphate ester hydrolysis is essential in signal transduction, energy storage and production, information storage and DNA repair. In this investigation, hydrolysis of adenosine monophosphate disodium salt (AMPNa2) was carried out in acidic, neutral and alkaline conditions of pH ranging between 0.30-12.71 at 60°C. The reaction was monitored spectrophotometrically. The rate ranged between (1.20 ± 0.10) × 10-7 s-1 to (4.44 ± 0.05) × 10-6 s-1 at [NaOH] from 0.0008 M to 1.00M recorded a second-order base-catalyzed rate constant, kOH as 4.32 × 10-6 M-1 s-1. In acidic conditions, the rate ranged between (1.32 ± 0.06) × 10-7 s-1 to (1.67 ± 0.10) × 10-6 s-1 at [HCl] from 0.01 M to 1.00 M. Second-order acid-catalyzed rate constant, kH obtained was 1.62 × 10-6 M-1 s-1. Rate of reaction for neutral region, k0 was obtained from graphical method to be 10-7 s-1. Mechanisms were proposed to involve P-O bond cleavage in basic medium while competition between P-O bond and N-glycosidic cleavage was observed in acidic medium. In conclusion, this study has provided comprehensive information on the kinetic parameters and mechanism of cleavage of AMPNa2 which mimicked natural AMP cleavage and the action of enzymes that facilitate its cleavage.

Alliance experience and performance outcomes: A meta-analysis

2021 ◽  
pp. 147612702098287
Author(s):  
Peng Wang ◽  
Xu Jiang ◽  
Maggie Chuoyan Dong
Keyword(s):  
Strategic Alliance ◽  
Meta Analysis ◽  
Group Analysis ◽  
Performance Outcomes ◽  
Country Level ◽  
Different Types ◽  
Performance Consequences ◽  
Controversial Topic ◽  
Alliance Experience ◽  
And Performance

Alliance experience has been a frequent topic in strategic alliance research in recent decades. Nonetheless, its performance consequences, either as a whole or differentiated into general versus partner-specific alliance experience, are neither theoretically clear nor empirically consistent. We use a range of meta-analytic techniques to integrate the empirical findings of 143 studies and provide a more conclusive assessment compared to prior research. Our study thus addresses a long-standing, understudied, and controversial topic: the distinction between the two types of alliance experiences. Going beyond traditional sub-group analysis, we reveal the contextual contingencies by examining how different types of alliance experiences and performance outcomes jointly affect the alliance experience–performance relationship. Moreover, we identify critical country-level institutional contingencies that moderate the focal effect.

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