scholarly journals Electrochemically Induced In-Situ Generated Co(OH)2 Nanoplates to Promote the Volmer Process Toward Efficient Alkaline Hydrogen Evolution Reaction

2020 ◽  
Author(s):  
Hong Liu ◽  
Jian-Jun Wang ◽  
Li-Wen Jiang ◽  
Yuan Huang ◽  
Bing Bing Chen ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Water Electrolysis ◽  
Water Dissociation ◽  
Alkaline Water Electrolysis ◽  
Additional Water ◽  
Dissociation Step ◽  
Insight Into

<p>Hydrogen production via alkaline water electrolysis is of significant interest. However, the additional water dissociation step makes the Volmer step a relatively more sluggish kinetics and consequently leads to a slower reaction rate than that in acidic solution. Herein, we demonstrate an effective strategy that Co(OH)<sub>2</sub> can promote the Volmer process by accelerating water dissociation and enhance the electrocatalytic performance of CoP toward alkaline hydrogen evolution reaction. The Co(OH)<sub>2</sub> nanoplates are electrochemically induced in-situ generated to form a nanotree-like structure with porous CoP nanowires, endowing the hybrid electrocatalyst with superior charge transportation, more exposed active sites, and enhanced reaction kinetics. This strategy may be extended to <a></a><a>other phosphides and chalcogenides </a>and provide insight into the design and fabrication of efficient alkaline HER catalysts.</p>

scholarly journals Electrochemically Induced In-Situ Generated Co(OH)2 Nanoplates to Promote the Volmer Process Toward Efficient Alkaline Hydrogen Evolution Reaction

2020 ◽  
Author(s):  
Hong Liu ◽  
Jian-Jun Wang ◽  
Li-Wen Jiang ◽  
Yuan Huang ◽  
Bing Bing Chen ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Water Electrolysis ◽  
Water Dissociation ◽  
Alkaline Water Electrolysis ◽  
Additional Water ◽  
Dissociation Step ◽  
Insight Into

<p>Hydrogen production via alkaline water electrolysis is of significant interest. However, the additional water dissociation step makes the Volmer step a relatively more sluggish kinetics and consequently leads to a slower reaction rate than that in acidic solution. Herein, we demonstrate an effective strategy that Co(OH)<sub>2</sub> can promote the Volmer process by accelerating water dissociation and enhance the electrocatalytic performance of CoP toward alkaline hydrogen evolution reaction. The Co(OH)<sub>2</sub> nanoplates are electrochemically induced in-situ generated to form a nanotree-like structure with porous CoP nanowires, endowing the hybrid electrocatalyst with superior charge transportation, more exposed active sites, and enhanced reaction kinetics. This strategy may be extended to <a></a><a>other phosphides and chalcogenides </a>and provide insight into the design and fabrication of efficient alkaline HER catalysts.</p>

Tungsten-doped Ni–Co phosphides with multiple catalytic sites as efficient electrocatalysts for overall water splitting

2019 ◽  
Vol 7 (28) ◽  
pp. 16859-16866 ◽  
Author(s):  
Shan-Shan Lu ◽  
Li-Ming Zhang ◽  
Yi-Wen Dong ◽  
Jia-Qi Zhang ◽  
Xin-Tong Yan ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Hydrogen Evolution Reaction ◽  
Alkaline Media ◽  
Water Dissociation ◽  
Overall Water Splitting ◽  
Catalytic Sites ◽  
Additional Water ◽  
Dissociation Step

The design of electrocatalysts including precious and nonprecious metals for the hydrogen evolution reaction (HER) in alkaline media remains challenging due to the sluggish reaction kinetics caused by the additional water dissociation step.

Engineering of Ru/Ru2P interfaces superior to Pt active sites for catalysis of the alkaline hydrogen evolution reaction

2019 ◽  
Vol 7 (10) ◽  
pp. 5621-5625 ◽  
Author(s):  
Zhao Liu ◽  
Zhe Li ◽  
Jing Li ◽  
Jie Xiong ◽  
Shunfa Zhou ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Synergistic Effects ◽  
Water Dissociation ◽  
Proton Reduction ◽  
Mass Activity

Based on the synergistic effects of Ru on water dissociation and Ru2P on proton reduction, Ru/Ru2P interfaces were engineered in situ, and the mass activity of the new catalyst for the alkaline HER was doubled compared to Pt/C.

Fabrication and Characterization of Amorphous Cobalt-Doped Molybdenum Sulfide for Hydrogen Evolution Reaction

2015 ◽  
Vol 15 (10) ◽  
pp. 8257-8262 ◽  
Author(s):  
Dongwook Lim ◽  
Hyein Hwang ◽  
Taewoo Kim ◽  
Sang Eun Shim ◽  
Sung-Hyeon Baeck
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Water Electrolysis ◽  
Molybdenum Sulfide ◽  
Intrinsic Activity ◽  
Metal Catalyst ◽  
Alkaline Water Electrolysis ◽  
Catalytic Hydrogen Evolution

In the present study, hydrogen evolution reaction (HER) by alkaline water electrolysis was conducted without using a precious metal catalyst. We synthesized an amorphous cobalt-doped molybdenum sulfide by electrodeposition using different cobalt loadings. The amorphous Co-MoSx produced was characterized by scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The cobalt doping and sulfidation procedure resulted in the successful fabrication of a candidate catalyst for the catalytic hydrogen evolution in alkaline solution with high intrinsic activity. Cobalt incorporated amorphous MoSx exhibited 3 times higher HER activity than non-promoted MoSx.

scholarly journals How Stable Are 2H-MoS2 Edges Under Hydrogen Evolution Reaction Conditions?

2021 ◽  
Author(s):  
Nawras Abidi ◽  
Audrey Bonduelle-Skrzypczak ◽  
Stephan Steinmann
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Density Functional ◽  
External Source ◽  
Operating Conditions ◽  
Adsorbed Hydrogen ◽  
Functional Theory ◽  
Acidic Conditions

MoS<sub>2</sub>, have emerged as a promising class of electrocatalysts for the production of H<sub>2</sub> via the hydrogen evolution reaction (HER) in acidic conditions.<div>The edges of MoS<sub>2</sub> are known for their HER activity, but their precise atomistic nature and stability under HER conditions is not yet known. In contrast to other typical uses of MoS<sub>2</sub> as a catalyst, under HER there is no external source of sulfur. Therefore, the sulfidation of the edges can only decrease under operating conditions and the thermodynamics of the process are somewhat ill-defined. Our results suggest that the 50%S S-edge may be active for HER via the Volmer-Tafel mechanism and is, despite a high H coverage, stable with respect to H<sub>2</sub>S release. </div><div>At the 50%S Mo-edge, the adsorbed hydrogen opens the way for H<sub>2</sub>S release, leading to the 0%S Mo-edge, which was previously investigated and found to be HER active. HER being a water-based process, we also considered the effect of the presence of H<sub>2</sub>O and the in-situ formation of OH. For the 50%S Mo-edge, H<sub>2</sub>O is only very weakly adsorbed and OH formation is unfavorable. Nevertheless, OH assists the loss of sulfur coverage, leading to OH-based HER active sites. In contrast, OH is strongly adsorbed on the 50%S S-edge. By explicitly considering the electrochemical potential using grand-canonical density functional theory, we unveil that the Volmer-Heyrovsky mechanism on sulfur sites is still accessible in the presence of surface OH at the 50%S S-edge. However, the 50%S S-edge is found to be mildly unstable with respect to H<sub>2</sub>S in the presence of water/OH. Hence, we suggest that the 50%S S-edge evolves over time towards a 0%S S-edge, covered by surface OH that will block permanently the active sites. </div>

scholarly journals Defect and Doping Engineered Penta-graphene for Catalysis of Hydrogen Evolution Reaction

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jinbo Hao ◽  
Feng Wei ◽  
Xinhui Zhang ◽  
Long Li ◽  
Chunling Zhang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Noble Metals ◽  
Low Cost ◽  
Water Electrolysis ◽  
Catalytic Performance ◽  
First Principles Calculation ◽  
Electron Charge Density ◽  
Calculation Results

AbstractWater electrolysis is a sustainable and clean method to produce hydrogen fuel via hydrogen evolution reaction (HER). Using stable, effective and low-cost electrocatalysts for HER to substitute expensive noble metals is highly desired. In this paper, by using first-principles calculation, we designed a defect and N-, S-, P-doped penta-graphene (PG) as a two-dimensional (2D) electrocatalyst for HER, and its stability, electronic properties and catalytic performance were investigated. The Gibbs free energy (ΔGH), which is the best descriptor for the HER, is calculated and optimized, the calculation results show that the ΔGH can be 0 eV with C2 vacancies and P doping at C1 active sites, which should be the optimal performance for a HER catalyst. Moreover, we reveal that the larger charge transfer from PG to H, the closer ΔGH is to zero according to the calculation of the electron charge density differences and Bader charges analysis. Ulteriorly, we demonstrated that the HER performance prefers the Volmer–Heyrovsky mechanism in this study.

In situ formed oxy/hydroxide antennas accelerating the water dissociation kinetics on a Co@N-doped carbon core–shell assembly for hydrogen production in alkaline solution

2019 ◽  
Vol 48 (31) ◽  
pp. 11927-11933 ◽  
Author(s):  
Tao Yang ◽  
Lang Pei ◽  
Shicheng Yan ◽  
Zhentao Yu ◽  
Tao Yu ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Alkaline Solution ◽  
Water Dissociation ◽  
Core Shell ◽  
Dissociation Kinetics ◽  
Alkaline Electrolytes ◽  
Carbon Core

The hydrogen evolution reaction (HER) in alkaline electrolytes is restricted severely by sluggish water dissociation in the Volmer step.

scholarly journals RuxSe@MoS2 hybrid as a highly efficient electrocatalyst toward hydrogen evolution reaction

RSC Advances ◽  
2019 ◽  
Vol 9 (24) ◽  
pp. 13486-13493 ◽  
Author(s):  
Qi Chen ◽  
Kefeng Wang ◽  
Jingjing Qin ◽  
Songzhu Wang ◽  
Wei Wei ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Hydrogen Adsorption ◽  
Water Dissociation ◽  
Highly Efficient

The bifunctionality mechanism of RuxSe@MoS2 greatly enhances the alkaline HER performance, in which Ru promotes water dissociation and the nearby Se atoms, unsaturated Mo and/or S atoms act as active sites for the intermediate hydrogen adsorption.

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