scholarly journals Kinetics of Hydrogen Generation from Oxidation of Hydrogenated Silicon Nanocrystals in Aqueous Solutions

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1413 ◽  
Author(s):  
Gauhar Mussabek ◽  
Sergei A. Alekseev ◽  
Anton I. Manilov ◽  
Sergii Tutashkonko ◽  
Tetyana Nychyporuk ◽  
...  
Keyword(s):  
Silicon Nanocrystals ◽  
Silicon Nanoparticles ◽  
Hydrogen Generation ◽  
Hydrogen Release ◽  
Water Molecules ◽  
Hydrogen Energy ◽  
Hydrogenated Silicon ◽  
Energy Applications ◽  
Kinetics Of ◽  
Silicon Nanopowders

Hydrogen generation rate is one of the most important parameters which must be considered for the development of engineering solutions in the field of hydrogen energy applications. In this paper, the kinetics of hydrogen generation from oxidation of hydrogenated porous silicon nanopowders in water are analyzed in detail. The splitting of the Si-H bonds of the nanopowders and water molecules during the oxidation reaction results in powerful hydrogen generation. The described technology is shown to be perfectly tunable and allows us to manage the kinetics by: (i) varying size distribution and porosity of silicon nanoparticles; (ii) chemical composition of oxidizing solutions; (iii) ambient temperature. In particular, hydrogen release below 0 °C is one of the significant advantages of such a technological way of performing hydrogen generation.

scholarly journals Hydrogen release from a single water molecule on Vn+ (3 ≤ n ≤ 30)

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Hanyu Zhang ◽  
Haiming Wu ◽  
Yuhan Jia ◽  
Baoqi Yin ◽  
Lijun Geng ◽  
...  
Keyword(s):  
Water Molecule ◽  
Hydrogen Generation ◽  
Human Life ◽  
Hydrogen Release ◽  
Water Molecules ◽  
Adsorbed Hydrogen ◽  
Dissociative Chemisorption ◽  
Hydrogen Atoms ◽  
Production Of Hydrogen ◽  
Single Water Molecule

Abstract Water and its interactions with metals are closely bound up with human life, and the reactivity of metal clusters with water is of fundamental importance for the understanding of hydrogen generation. Here a prominent hydrogen evolution reaction (HER) of single water molecule on vanadium clusters Vn+ (3 ≤ n ≤ 30) is observed in the reaction of cationic vanadium clusters with water at room temperature. The combined experimental and theoretical studies reveal that the wagging vibrations of a V-OH group give rise to readily formed V-O-V intermediate states on Vn+ (n ≥ 3) clusters and allow the terminal hydrogen to interact with an adsorbed hydrogen atom, enabling hydrogen release. The presence of three metal atoms reduces the energy barrier of the rate-determining step, giving rise to an effective production of hydrogen from single water molecules. This mechanism differs from dissociative chemisorption of multiple water molecules on aluminium cluster anions, which usually proceeds by dissociative chemisorption of at least two water molecules at multiple surface sites followed by a recombination of the adsorbed hydrogen atoms.

Kinetics of Light-Induced Effects in Mixed-Phase Hydrogenated Silicon Solar Cells

2003 ◽  
Vol 762 ◽  
Author(s):  
Guozhen Yuea ◽  
Baojie Yan ◽  
Jeffrey Yang ◽  
Kenneth Lord ◽  
Subhendu Guha
Keyword(s):  
Solar Cells ◽  
Fill Factor ◽  
Equivalent Circuit Model ◽  
Open Circuit ◽  
Mixed Phase ◽  
Silicon Solar Cells ◽  
Initial Increase ◽  
Soaking Time ◽  
Hydrogenated Silicon ◽  
Kinetics Of

AbstractWe have observed a significant light-induced increase in the open-circuit voltage (Voc) of mixed-phase hydrogenated silicon solar cells. In this study, we investigate the kinetics of the light-induced effects. The results show that the cells with different initial Voc have different kinetic behavior. For the cells with a low initial Voc (less than 0.8 V), the increase in Voc is slow and does not saturate for light-soaking time of up to 16 hours. For the cells with medium initial Voc (0.8 ∼ 0.95 V), the Voc increases rapidly and then saturates. Cells with high initial Voc (0.95 ∼ 0.98 V) show an initial increase in Voc, followed bya Voc decrease. All light-soaked cells exhibit a degradation in fill factor. The temperature dependence of the kinetics shows that light soaking at high temperatures causes Voc increase to saturate faster than at low temperatures. The observed results can be explained by our recently proposed two-diode equivalent-circuit model for mixed-phase solar cells.

Engineering Ru atomic structures toward enhanced kinetics of hydrogen generation

2021 ◽  
Vol 235 ◽  
pp. 116507
Author(s):  
Wenzhao Fu ◽  
Qianhong Wang ◽  
Wenyao Chen ◽  
Gang Qian ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Hydrogen Generation ◽  
Atomic Structures ◽  
Kinetics Of

Photocatalytic hydrogen generation using mesoporous silicon nanoparticles: influence of magnesiothermic reduction conditions and nanoparticle aging on the catalytic activity

Nanoscale ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 2685-2692
Author(s):  
Isabel S. Curtis ◽  
Ryan J. Wills ◽  
Mita Dasog
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Production ◽  
Silicon Nanoparticles ◽  
Hydrogen Generation ◽  
Oxide Content ◽  
Magnesiothermic Reduction ◽  
Mesoporous Silicon ◽  
High Crystallinity ◽  
Photocatalytic Hydrogen Generation

High crystallinity, low oxide content, and low sintering lead to optimally performing mesoporous Si photocatalysts for solar-driven hydrogen production.

CATALYTIC PROPERTIES OF Ni-V COATING IN THE PROCESS OF HYDROGEN RELEASE

2021 ◽  
pp. 41-47
Author(s):  
N. Rudenko ◽  
S. Leshchenko ◽  
Yu. Kovalenko
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Electrode Materials ◽  
Voltage Drop ◽  
Hydrogen Release ◽  
Hydrogen Energy ◽  
Industrial Facilities ◽  
Alkaline Electrolysis ◽  
Electrolytic Alloys ◽  
Steel Electrodes

Solar and hydrogen energy play an important role in providing a variety of industrial facilities with electricity and heat. One of the priorities of modern industry is to increase the production of environmentally friendly energy source – electrochemical synthesis of hydrogen. Modern methods of electrolysis of water do not meet the need for its use, due to the high cost of electrosynthesis of water-alkaline electrolysis, which depends on the material and energy consumption of electrolysis. The useful energy consumption for the production of energy – hydrogen at the cathode and "unnecessary" costs - for the release of oxygen at the anode, depend on the overvoltage of the respective reactions. Therefore, the most important problem of hydrogen energy is the synthesis of electrode materials with low overvoltage of O2 and H2. Electrode materials with low overvoltage will reduce the specific consumption of electricity in obtaining hydrogen by "classical" electrolysis. The prospects of reducing the cathodic and anodic overvoltage, which is a significant part of the voltage at the terminals of the cell, for the development of highly efficient and competitive technologies for hydrogen production by low-temperature electrolysis of an alkaline solution have been theoretically substantiated and experimentally confirmed. To reduce the overvoltage of the cathodic hydrogen evolution, it is proposed to modify the surface of the cathodes. The application of a small amount of electrolytic alloys of metals of the iron family with molybdenum and tungsten on nickel, cobalt, titanium and steel electrodes significantly (by 40–50 %) reduces the overvoltage of cathodic release of hydrogen from alkali solution. The use of steel electrodes, the surface of which is modified with vanadium and ni-ckel, reduces the voltage drop on the cell during the synthesis of H2 and O2 by 0.2–0.3 V, which creates conditions for reducing energy costs and energy savings.

scholarly journals SOLVATION OF THE [Cr(NCS)4(IMIDAZOLE)2] ION IN ETHANOL-WATER MIXTURES

2002 ◽  
Vol 10 (11) ◽  
pp. 63-72
Author(s):  
lon Ganescu ◽  
George Bratulescu ◽  
Ion Papa ◽  
Anca Ganescu ◽  
Alin Barbu ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Order Reaction ◽  
Water Molecules ◽  
Hydrogen Ions ◽  
Second Order Reaction ◽  
Acidic Solutions ◽  
The Third ◽  
Competitive Reactions ◽  
Different Temperatures ◽  
Kinetics Of

Salvation kinetics of [Cr(NCS)4(imidazole)2]- has been studied in ethanol-water mixtures at different temperatures. The first stage of the solvation consists of two competitive reactions: two NCS- ions are exchanged, presumably, by water molecules and simultaneously an imidazole molecule by ethanol, the latter in a second-order reaction, accelerated by hydrogen ions. The exchange of the amine is followed by the substitution of the first two NCS- ions. The third and fourth NCS- ions are substituted only in neutral and slightly acidic solutions. Kinetic parameters have been determined for reactions (1), (2), and (4). The influence of the solvent composition and acidity is discussed

scholarly journals Study of Hydrogen Generation of Aluminum-Containing Compositions with Boric Acid

2018 ◽  
Vol 3 (3) ◽  
pp. 230
Author(s):  
Salakhova A.A. ◽  
Suvorov V.A. ◽  
Firsova A. I. ◽  
Belozerov V.I. ◽  
Milinchuk V.K.
Keyword(s):  
Boric Acid ◽  
Hydrogen Generation ◽  
Sodium Metasilicate ◽  
Chemical Processes ◽  
System Management ◽  
Control Rod ◽  
Radiation Fields ◽  
Fuel Elements ◽  
And Control ◽  
Kinetics Of

The results of investigations of the kinetics of hydrogen generation compositions with aluminum, chemical activators (hydrated sodium metasilicate, oxide and calcium hydroxide) boric acid. Aluminium and its alloys used for the manufacture of protective sheaths of fuel elements and control rod protection system management, pipelines, tanks, and various support structures in the active zone of atomic reactors RBMK, research water-cooled reactors. The aluminum is protected from direct contact with water and steam surface layer of metal oxide having a high corrosion resistance at high temperatures in powerful radiation fields. However, after removal or when the discontinuity of the oxide layer of activated metal efficiently decompose water to hydrogen. It is established that the hydrogen aluminum-containing compositions is dependent on the concentration of boric acid. The discovery of the involvement of boric acid in these reactions expands the ideas about regularities of chemical processes of formation of hydrogen flowing in the water coolant of VVER reactors with the participation of the corrective additives and impurities.

Sign in / Sign up

Export Citation Format

Share Document