Molybdenum carbide nanocrystal embedded N-doped carbon nanotubes as electrocatalysts for hydrogen generation

2015 ◽  
Vol 3 (11) ◽  
pp. 5783-5788 ◽  
Author(s):  
Kai Zhang ◽  
Yang Zhao ◽  
Diyu Fu ◽  
Yujin Chen
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Molybdenum Carbide ◽  
Hydrogen Generation ◽  
Cathodic Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Cathodic Current

Highly conductive N-doped carbon nanotubes embedded with molybdenum carbide nanocrystals with a size less than 3 nm exhibit superior activity for the hydrogen evolution reaction, including small overpotential, large cathodic current density and high exchange current density.

Correlation of Exchange Current Density j₀ and the Standard Potential of the Metal Electrodes EM⁰ for the Hydrogen Evolution Reaction (HER)

2020 ◽  
Vol MA2020-01 (46) ◽  
pp. 2604-2604
Author(s):  
Daniel Lee Parr ◽  
Kasun Dadallagei ◽  
Sidney J. DeBie ◽  
Joshua R Coduto ◽  
Christian D Haas ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Standard Potential ◽  
Metal Electrodes

Correlation of Exchange Current Density j₀ and the Standard Potential of the Metal Electrodes E0 M : A Different View of the Hydrogen Evolution Reaction (HER)

2021 ◽  
Vol MA2021-01 (46) ◽  
pp. 1864-1864
Author(s):  
Daniel Parr ◽  
Kasun Saweendra Rathnatunga Dadallagei ◽  
Sidney Debie ◽  
Joshua Richard Coduto ◽  
Christian D Haas ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Standard Potential ◽  
Metal Electrodes

scholarly journals Atomic Pt-Clusters Decoration Triggers a High-Rate Performance on Ni@Pd Bimetallic Nanocatalyst for Hydrogen Evolution Reaction in Both Alkaline and Acidic Medium

2020 ◽  
Vol 10 (15) ◽  
pp. 5155 ◽  
Author(s):  
Dinesh Bhalothia ◽  
Sheng-Po Wang ◽  
Shuan Lin ◽  
Che Yan ◽  
Kuan-Wen Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Acidic Medium ◽  
Lattice Mismatch ◽  
Cathodic Current Density ◽  
Green Energy ◽  
High Rate ◽  
Pt Catalyst ◽  
Cathodic Current

The development of inexpensive and highly robust nanocatalysts (NCs) to boost electrochemical hydrogen evolution reaction (HER) strengthens the implementation of several emerging sustainable-energy technologies. Herein, we proposed a novel nano-architecture consisting of a hierarchical structured Ni@Pd nanocatalyst with Pt-clusters decoration on the surface (denoted by Ni@Pd-Pt) for HER application in acidic (0.5 M H2SO4) and alkaline (0.1 M KOH) mediums. The Ni@Pd-Pt NC is fabricated on a carbon black support via a “self-aligned” heterogeneous nucleation-crystal growth mechanism with 2 wt.% Pt-content. As-prepared Ni@Pd-Pt NC outperforms the standard Pt/C (30 wt.% Pt) catalyst in HER and delivers high-rate catalytic performance with an ultra-low overpotential (11.5 mV) at the cathodic current density of 10 mA∙cm−2 in alkaline medium, which is 161.5 mV and 14.5 mV less compared to Ni@Pd (173 mV) and standard Pt/C (26 mV) catalysts, respectively. Moreover, Ni@Pd-Pt NC achieves an exactly similar Tafel slope (42 mV∙dec−1) to standard Pt/C, which is 114 mV∙dec−1 lesser when compared to Ni@Pd NC. Besides, Ni@Pd-Pt NC exhibits an overpotential value of 37 mV at the current density of 10 mA cm−2 in acidic medium, which is competitive to standard Pt/C catalyst. By utilizing physical characterizations and electrochemical analysis, we demonstrated that such an aggressive HER activity is dominated by the increased selectivity during HER due to the reduced competition between intermediate products on the non-homogeneous NC surface. This phenomenon can be rationalized by electron localization owing to the electronegative difference (χPt > χPd > χNi) and strong lattice mismatch at the Ni@Pd heterogeneous binary interfaces. We believe that the obtained results will significantly provide a facile design strategy to develop next-generation heterogenous NCs for HER and related green-energy applications

A robust electrocatalytic activity toward the hydrogen evolution reaction from W/W2C heterostructured nanoparticles coated with a N,P dual-doped carbon layer

2019 ◽  
Vol 55 (65) ◽  
pp. 9665-9668 ◽  
Author(s):  
Quan Zhang ◽  
Fang Luo ◽  
Hao Hu ◽  
Ruizhi Xu ◽  
Konggang Qu ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Electrocatalytic Activity ◽  
Carbon Layer ◽  
Cathodic Current Density ◽  
Cathodic Current ◽  
Alkaline Electrolytes

W/W2C heterostructured nanoparticles encapsulated by N,P dual-doped carbon require low overpotentials of 55 mV and 82 mV vs. RHE to achieve cathodic current density of 10 mA cm−2 in acidic and alkaline electrolytes, respectively.

scholarly journals Metal powder electrolysis: The shape of powder particles as a function of the exchange current density and overpotential for hydrogen evolution reaction

2020 ◽  
Vol 85 (3) ◽  
pp. 347-352
Author(s):  
Nebojsa Nikolic
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Dendritic Growth ◽  
Three Dimensional ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Two Dimensional ◽  
Molten Salt Electrolysis ◽  
Powder Particles

The short survey of the dependence of the shape of electrolytically produced powder particles on the exchange current density for metal deposition and overpotential for hydrogen evolution reaction is presented. The decrease of the exchange current density leads to a branching of dendrites and their transformation from needle-like and the two-dimensional (2D) fern-like to the three-dimensional (3D) pine-like shapes. Vigorous hydrogen evolution inhibits the dendritic growth leading to a formation of cauliflower-like and the spongy-like particles. The very thin needles were obtained by molten salt electrolysis. Mechanisms responsible for the formation of both the dendritic (the general theory of disperse deposits formation) and the cauliflower-like and the spongy-like particles (the concept of ?effective overpotential?) were also mentioned.

scholarly journals Influence of the exchange current density and overpotential for hydrogen evolution reaction on the shape of electrolytically produced disperse forms - Review

2020 ◽  
Vol 10 (2) ◽  
pp. 111-126
Author(s):  
Nebojša D. Nikolić
Keyword(s):  
Molten Salt ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Magnesium Nitrate ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Nitrate Hexahydrate ◽  
Molten Salt Electrolysis ◽  
Magnesium Nitrate Hexahydrate

In this study, comprehensive survey of formation of disperse forms by the electrolysis from aqueous electrolytes and molten salt electrolysis has been presented. The shape of electrolitically formed disperse forms primarily depends on the nature of metals, determined by the exchange current density (j0) and overpotential for hydrogen evolution reaction as a parallel reaction to metal electrolysis. The decrease of the j0 value leads to a change of shape of dendrites from the needle-like and the 2D fern-like dendrites (metals characterized by high j0 values) to the 3D pine-like dendrites (metals characterized by medium j0 values). The appearing of a strong hydrogen evolution leads to formation of cauliflower-like and spongy-like forms (metals characterized by medium and low j0 values). The other disperse forms, such as regular and irregular crystals, granules, cobweb-like, filaments, mossy and boulders, usually feature metals characterized by the high j0 values. The globules and the carrot-like forms are a characteristic of metals with the medium j0 values. The very long needles were a product of molten salt electrolysis of magnesium nitrate hexahydrate. Depending on the shape of the disperse forms, i.e. whether they are formed without and with vigorous hydrogen evolution, formation of all disperse forms can be explained by either application of the general theory of disperse deposits formation or the concept of "effective overpotential". With the decrease of j0 value, the preferred orientation of the disperse forms changed from the strong (111) in the needle-like and the fern-like dendrites to randomly oriented crystallites in the 3D pine-like dendrites and the cauliflower-like and the spongy-like forms.

MOF-derived nanostructured cobalt phosphide assemblies for efficient hydrogen evolution reaction

RSC Advances ◽  
2015 ◽  
Vol 5 (110) ◽  
pp. 90265-90271 ◽  
Author(s):  
Lili Li ◽  
Xingyue Li ◽  
Lunhong Ai ◽  
Jing Jiang
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
High Performance ◽  
Cathodic Current Density ◽  
Cathodic Current ◽  
Zeolitic Imidazolate Framework ◽  
Cobalt Phosphide ◽  
Low Overpotential

Zeolitic imidazolate framework-67 derived nanostructured CoP assemblies exhibited high-performance for electrochemical HER, as manifested by a low overpotential, a large cathodic current density and an excellent durability.

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