Efficient Hydrogen Evolution on Cu Nanodots-Decorated Ni3S2 Nanotubes by Optimizing Atomic Hydrogen Adsorption and Desorption

2018 ◽  
Vol 140 (2) ◽  
pp. 610-617 ◽  
Author(s):  
Jin-Xian Feng ◽  
Jin-Qi Wu ◽  
Ye-Xiang Tong ◽  
Gao-Ren Li
2019 ◽  
Vol 123 (43) ◽  
pp. 26662-26672 ◽  
Author(s):  
Björn Arndt ◽  
Marcus Creutzburg ◽  
Elin Grånäs ◽  
Sergey Volkov ◽  
Konstantin Krausert ◽  
...  

CrystEngComm ◽  
2021 ◽  
Author(s):  
Qian Zhang ◽  
Shuihua Tang ◽  
Lieha Shen ◽  
Weixiang Yang ◽  
Zhen Tang ◽  
...  

Developing cost-effective and high-performance electrocatalysts for hydrogen evolution reaction (HER) are imperative thanks to rapid increase of fuel-cell driven vehicles. Tungsten (W) possesses advantages of optimized hydrogen adsorption energy and...


Vacuum ◽  
1994 ◽  
Vol 45 (2-3) ◽  
pp. 299-301 ◽  
Author(s):  
L. Stobiński ◽  
R. Duś

1970 ◽  
Vol 43 (1) ◽  
pp. 103-116 ◽  
Author(s):  
M Ashraful Islam Molla ◽  
Mithun Sarker ◽  
AKM Fazle Kibria

Redox behaviors and hydrogen evolution efficiencies of Pd and Mo deposited Pd electrodes have been investigated in 30wt.% KOH electrolyte by cyclic voltammetry. Cyclic voltammograms of Pd electrode in between the potential range - 1.05 V to + 0.75 V showed two couples of redox peaks for the transformations of Pd(0) ←→ Pd(OH)2 and Pd(OH)2 ←→ PdOOH, an anodic peak for the desorption of diffusional hydrogen (dH) and hydrogen and oxygen evolutions at the terminal potential regions. Hydrogen evolution efficiency found decreased with time and then reached to a stable condition after 35 minutes. In presence of deposited Mo, the electrode stable condition appeared after 10 minutes only. Pd found predominates over deposited Mo. Both the Pd(0) ←Pd(OH)2 and Mo(0) ← Mo(OH)2 transformations appeared at the same potential value. Mo stopped the movement of hydrogen adsorption and absorption region of Pd electrode towards negative potential direction. It increased the hydrogen evolution efficiency of Pd electrode remarkably. At the potentials - 1.1 V, - 1.2 V, - 1.25 V and - 1.3 V, currents for Pd + Mo system found 1.44, 1.25, 1.20, 1.23 times higher than those of Pd electrode. Mo also showed hydrogen migratory role to the fraction of Pd surface covered by it. Hydrogen evolution reactions (HER) over Pd and Pd + Mo surfaces seemed followed similar mechanisms. Tafel plots for the HER for both the systems showed two Tafel regions. Exchange current density values (io) for the low and high overpotential regions of Pd + Mo system showed 2.85 times and 1.29 times higher values than those of Pd electrode. Key words: Pd, Pd-Mo, Hydrogen evolution efficiency, Hydrogen evolution reactions (HER) DOI: 10.3329.bjsir.v43i1.861 Bangladesh J. Sci. Ind. Res. 43(1), 103-116, 2008


Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 307
Author(s):  
Russell W. Cross ◽  
Nelson Y. Dzade

Nickel phosphide (Ni2P) is a promising material for the electrocatalytic generation of hydrogen from water. Here, we present a chemical picture of the fundamental mechanism of Volmer–Tafel steps in hydrogen evolution reaction (HER) activity under alkaline conditions at the (0001) and (10 1 ¯ 0) surfaces of Ni2P using dispersion-corrected density functional theory calculations. Two terminations of each surface (Ni3P2- and Ni3P-terminated (0001); and Ni2P- and NiP-terminated (10 1 ¯ 0)), which have been shown to coexist in Ni2P samples depending on the experimental conditions, were studied. Water adsorption on the different terminations of the Ni2P (0001) and (10 1 ¯ 0) surfaces is shown to be exothermic (binding energy in the range of 0.33−0.68 eV) and characterized by negligible charge transfer to/from the catalyst surface (0.01−0.04 e−). High activation energy barriers (0.86−1.53 eV) were predicted for the dissociation of water on each termination of the Ni2P (0001) and (10 1 ¯ 0) surfaces, indicating sluggish kinetics for the initial Volmer step in the hydrogen evolution reaction over a Ni2P catalyst. Based on the predicted Gibbs free energy of hydrogen adsorption (ΔGH*) at different surface sites, we found that the presence of Ni3-hollow sites on the (0001) surface and bridge Ni-Ni sites on the (10 1 ¯ 0) surface bind the H atom too strongly. To achieve facile kinetics for both the Volmer and Heyrovsky–Tafel steps, modification of the surface structure and tuning of the electronic properties through transition metal doping is recommended as an important strategy.


2018 ◽  
Vol 8 (12) ◽  
pp. 2466 ◽  
Author(s):  
Yang Wu ◽  
Zhongmin Wang ◽  
Dianhui Wang ◽  
Jiayao Qin ◽  
Zhenzhen Wan ◽  
...  

To investigate Mo doping effects on the hydrogen permeation performance of Nb membranes, we study the most likely process of atomic hydrogen adsorption and diffusion on/into Mo-doped Nb (100) surface/subsurface (in the Nb12Mo4 case) via first-principles calculations. Our results reveal that the (100) surface is the most stable Mo-doped Nb surface with the smallest surface energy (2.75 J/m2). Hollow sites (HSs) in the Mo-doped Nb (100) surface are H-adsorption-favorable mainly due to their large adsorption energy (−4.27 eV), and the H-diffusion path should preferentially be HS→TIS (tetrahedral interstitial site) over HS→OIS (octahedral interstitial site) because of the correspondingly lower H-diffusion energy barrier. With respect to a pure Nb (100) surface, the Mo-doped Nb (100) surface has a smaller energy barrier along the HS→TIS pathway (0.31 eV).


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