Polarisation cathodique en milieu alcalin des alliages Nb–Co

1981 ◽  
Vol 59 (8) ◽  
pp. 1261-1266 ◽  
Author(s):  
Y. Umetsu ◽  
D. L. Piron ◽  
G. Bélanger
Keyword(s):  
Solid Solution ◽  
Optical Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Cathodic Polarization ◽  
Electrochemical Activity ◽  
Surface Degradation ◽  
Δ Phase ◽  
The One ◽  
Increased Activity

NbCo alloys were prepared and their composition characterized by optical microscopy. These alloys were evaluated for their electrochemical activity towards the hydrogen evolution reaction (HER) at 25 °C in a 25% KOH solution. The alloys between 20 and 70wt% Co showed an increased activity compared to their parent metals. However the activity is below the one observed for pure Ni. As for the NbNi alloys, the NbCo undergo some surface degradation under prolonged (6 h) cathodic polarization at 400–700 mA cm−2. This disintegration of the surfaces is observed for alloys below 50% in Co. Above this proportion, the alloys remain stable towards the RDH. This degradation is associated with the presence of the δ phase in the alloy: this phase is the solid solution of Nb in the alloy.

Controllable synthesis of Mo2C with different morphology and application to electrocatalytic hydrogen evolution reaction

2021 ◽  
Author(s):  
He-qiang Chang ◽  
Guo-Hua Zhang ◽  
Kuo-Chih Chou
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Structural Design ◽  
Superior Performance ◽  
Controllable Synthesis ◽  
Nitridation Reaction ◽  
Special Surface ◽  
One Step ◽  
The One ◽  
Insight Into

Abstract In order to evaluate the effect of precursors and synthesis strategies on catalytic ability of Mo2C in the hydrogen evolution reaction (HER), four kinds of Mo2C were synthesized using two kinds of MoO3 by two strategies. Compared with the one-step direct carbonization strategy, Mo2C with a large special surface area and a better performance could be synthesized by the two-step strategy composed of a nitridation reaction and a carbonization reaction. Additionally, the as-prepared porous Mo2C nanobelts (NBs) exhibit good electrocatalytic performance with a small overpotential of 165 mV (0.5 M H2SO4) and 124 mV (1 M KOH) at 10 mA cm-2, as well as a Tafel slope of 58 mV dec-1 (0.5 M H2SO4) and 59 mV dec-1 (1 M KOH). The excellent catalytic activity is ascribed to the nano crystallites and porous structure. What’s more, the belt structure also facilitates the charge transport in the materials during the electrocatalytic HER process. Therefore, the two-step strategy provides a new insight into the structural design with superior performance for electrocatalytic HER.

Nanocrystalline Ni-Mo alloys and their application in electrocatalysis

1994 ◽  
Vol 9 (11) ◽  
pp. 2998-3008 ◽  
Author(s):  
R. Schulz ◽  
J.Y. Huot ◽  
M.L. Trudeau ◽  
L. Dignard-Bailey ◽  
Z.H. Yan ◽  
...  
Keyword(s):  
Solid Solution ◽  
Hydrogen Evolution ◽  
Amorphous Phase ◽  
Hydrogen Evolution Reaction ◽  
Supersaturated Solid Solution ◽  
Milling Process ◽  
Alkaline Solutions ◽  
Nanocrystalline State ◽  
Mo Content ◽  
Nanocrystalline Phases

The structural and electrocatalytic properties of metastable Ni-Mo alloys have been investigated for the hydrogen evolution reaction in alkaline solutions. Amorphous and nanocrystalline phases have been prepared by mechanically alloying the elemental components under various milling conditions. Fcc nanocrystals are formed when the Mo concentration is smaller than 30 at. %. The nanocrystalline state becomes unstable with respect to the amorphous phase when the Mo content in the solid solution exceeds 30 at. %. The electroactive phase for the hydrogen evolution reaction in alkaline solutions is the nanocrystalline supersaturated solid solution. The presence of oxygen during the milling process improves the properties of the alloys.

Electrochemical activity of 1T′ structured rhenium selenide nanosheets via electronic structural modulation from selenium-vacancy generation

2018 ◽  
Vol 6 (45) ◽  
pp. 22526-22533 ◽  
Author(s):  
Yuan Sun ◽  
Jie Meng ◽  
Huanxin Ju ◽  
Junfa Zhu ◽  
Qunxiang Li ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Electrochemical Activity ◽  
Controllable Synthesis ◽  
Vacancy Generation ◽  
Structural Modulation

The controllable synthesis of 1T′ structured ReSe2−x nanosheets with Se vacancies was achieved; the nanosheets were used as an efficient electrocatalyst for the hydrogen evolution reaction.

Increased activity in hydrogen evolution electrocatalysis for partial anionic substitution in cobalt oxysulfide nanoparticles

2016 ◽  
Vol 4 (8) ◽  
pp. 2842-2848 ◽  
Author(s):  
Andrew Nelson ◽  
Kevin E. Fritz ◽  
Shreyas Honrao ◽  
Richard G. Hennig ◽  
Richard D. Robinson ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Anion Exchange ◽  
Hydrogen Evolution Reaction ◽  
Adsorption Energy ◽  
Increased Activity

Metastable CoOxSy electrocatalysts for the hydrogen evolution reaction were prepared by anion exchange. Lightly doped CoOxS0.18 is 2–3 times more active than either end-member of the substitution series due to optimized H adsorption energy.

scholarly journals Catalysis: NiMo Solid Solution Nanowire Array Electrodes for Highly Efficient Hydrogen Evolution Reaction (Adv. Funct. Mater. 44/2019)

2019 ◽  
Vol 29 (44) ◽  
pp. 1970308
Author(s):  
Adeela Nairan ◽  
Peichao Zou ◽  
Caiwu Liang ◽  
Jiaxing Liu ◽  
Dang Wu ◽  
...  
Keyword(s):  
Solid Solution ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Nanowire Array ◽  
Highly Efficient

scholarly journals Effect of Morphology and Mechanical Stability of Nanometric Platinum Layer on Nickel Foam for Hydrogen Evolution Reaction

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3116
Author(s):  
Rachela G. Milazzo ◽  
Stefania M. S. Privitera ◽  
Silvia Scalese ◽  
Salvatore A. Lombardo
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Deposition Time ◽  
Mechanical Stability ◽  
Nickel Foam ◽  
Linear Sweep Voltammetry ◽  
Electrochemical Activity ◽  
Alkaline Electrolyte ◽  
Mechanical Instability ◽  
Platinum Layer

Platinum thin films are deposited on open-cell nickel foam with porosity of 95% via spontaneous galvanic displacement. Ni foams with different morphologies and pore size are compared and characterized by electrochemical and structural analysis techniques. The effect of Pt coating on the electrochemical activity is studied by using the Pt coated foam as electrode material for hydrogen evolution reaction in an aqueous alkaline electrolyte. The electrocatalytic activity of the electrodes is evaluated using linear sweep voltammetry curves and Tafel plots as a function of deposition time. The comparison with scanning electron microscopy analyses demonstrates that the catalytic activity has a maximum when the platinum film completely covers the Ni surface. The further increase of the Pt thickness leads to mechanical instability with crack formation and delamination. The effect of the foam morphology on the Pt deposition rate has been evaluated and discussed, determining the minimum Pt amount required to achieve the maximum electrochemical activity, as well as the maximum thickness in order to assure stable characteristics before delamination occurs.

Molten Salt Synthesized MgNiO2 Micro/Nano-Particles for High Energy Density Supercapacitor and Electrocatalyst for Hydrogen Evolution Reaction in Alkaline Medium

2021 ◽  
Vol 21 (11) ◽  
pp. 5556-5568
Author(s):  
S. Maitra ◽  
R. Mitra ◽  
T. K. Nath
Keyword(s):  
Solid Solution ◽  
Energy Density ◽  
Molten Salt ◽  
Hydrogen Evolution ◽  
Alkaline Medium ◽  
Hydrogen Evolution Reaction ◽  
High Energy ◽  
Nano Particles ◽  
High Energy Density ◽  
Phonon Modes

In recent years, solid solutions have shown promising results as functional materials for different applications. These materials have tunable physiochemical properties and electronic properties, and are being intensively studied for next generation electrochemical charge storage as well as noble metal free low cost electrocatalyts. In the present work, Magnesium Nickel Oxide (MgNiO2) solid solution is prepared by molten salt synthesis. MgNiO2 particles having octahedron shaped morphology with size of 550 nm with an agglomerative behavior was observed through morphological studies. Raman studies revealed presence of three two-phonon modes as well as two one-phonon modes, which confirm the phase purity of MgNiO2 sample. MgNiO2 particles behaved as a promising supercapacitor candidate by exhibiting a large specific capacitance of 76 F/g. It also revealed electrochemical stability over an expansive potential range under the presence of 0.5 mol L-1Sodium Sulfate (Na2SO4) electrolyte, having a high energy density of nearly 51 Wh/kg with a power density of nearly 825 w/kg. Further, MgNiO2 particle showed improved electrocatalytic potential towards Hydrogen Evolution Reaction (HER) in 1 mol L-1 Potassium Hydroxide (KOH) alkaline medium, by demonstrating an overpotential of 0.636 V with a Tafel slope of 0.22205 v/dec. Based on these observed promising results, it can be conclusively inferred that MgNiO2 solid solution is a potential candidate for environmental friendly high voltage supercapacitor and HER electrocatalyst applications.

Sign in / Sign up

Export Citation Format

Share Document