First-Principles Study of Atomic Hydrogen and Oxygen Adsorption on Doped-Iron Nanoclusters

2016 ◽  
Author(s):  
Nishith K. Das ◽  
T. Shoji
Keyword(s):  
Density Functional ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculations ◽  
Minor Element ◽  
Oxygen Adsorption ◽  
Ground State Structure ◽  
Small Contribution ◽  
Functional Theory ◽  
Strong Hybridization ◽  
A Minor

Density functional theory calculations have been used to calculate the ground state structure and oxygen and hydrogen adsorption properties of the pure and doped-iron nanoclusters. Small atomic clusters containing two to six atoms have been considered and a single Fe atom has replaced by a minor element i.e. Zr, Ti, and Sc. Doping of a minor element increases the cluster stability and octahedron Fe5Zr is the most stable structure within this study. Zr- and Sc-doped clusters have the highest oxygen and hydrogen adsorption energy. The electronic structure shows a strong hybridization between the metal 3d and oxygen 2p orbitals with a small contribution from metal 4s and 3p orbitals. Additionally, H s and metal 4s states form a new peak below the Fermi energy and a small modification is observed for 3d orbitals near the Fermi level. A small amount of Zr- and Sc-doping into the Fe-based alloys might improve the oxide film adherence.

scholarly journals First-Principles Mechanistic Insights into the Hydrogen Evolution Reaction on Ni2P Electrocatalyst in Alkaline Medium

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 307
Author(s):  
Russell W. Cross ◽  
Nelson Y. Dzade
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculations ◽  
Transition Metal Doping ◽  
Experimental Conditions ◽  
Functional Theory ◽  
Alkaline Conditions ◽  
Modification Of The Surface

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.

scholarly journals Excess charge driven dissociative hydrogen adsorption on Ti2O4−

2017 ◽  
Vol 19 (34) ◽  
pp. 23154-23161 ◽  
Author(s):  
Xiaowei Song ◽  
Matias R. Fagiani ◽  
Sreekanta Debnath ◽  
Min Gao ◽  
Satoshi Maeda ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculations ◽  
Excess Charge ◽  
Functional Theory

The mechanism of dissociative D2 adsorption on Ti2O4− is studied using infrared photodissociation spectroscopy in combination with density functional theory calculations.

scholarly journals Size-dependent trends in the hydrogen evolution activity and electronic structure of MoS2 nanotubes

2021 ◽  
Author(s):  
Charlie Ruffman ◽  
James Thomas Alan Gilmour ◽  
Anna L. Garden
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Hydrogen Evolution ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculations ◽  
Free Energies ◽  
Functional Theory ◽  
Size Dependent ◽  
First Time

The thermodynamics of hydrogen evolution on MoS2 nanotubes is studied for the first time using periodic density functional theory calculations to obtain hydrogen adsorption free energies (ΔGH ads) on pristine...

scholarly journals A DFT+U investigation of hydrogen adsorption on the LaFeO3(010) surface

2017 ◽  
Vol 19 (10) ◽  
pp. 7399-7409 ◽  
Author(s):  
Isaac W. Boateng ◽  
Richard Tia ◽  
Evans Adei ◽  
Nelson Y. Dzade ◽  
C. Richard A. Catlow ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Adsorption Mechanism ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculations ◽  
Nickel Metal ◽  
Functional Theory ◽  
Nickel Metal Hydride ◽  
Lanthanum Ferrite ◽  
Spin Polarized

Lanthanum ferrite (LaFeO3) is a technologically important electrode material for nickel–metal hydride batteries, energy storage and catalysis. In the present study, we have employed spin-polarized density functional theory calculations, with the Hubbard U correction (DFT+U), to unravel the adsorption mechanism of H2 on the LaFeO3(010) surface.

Adsorption of Hydrogen Molecule on the Intrinsic and Al-Doped Graphene: A First Principle Study

2012 ◽  
Vol 507 ◽  
pp. 61-64 ◽  
Author(s):  
Ye Lu He ◽  
Ding Xing Liu ◽  
Yong Qu ◽  
Zhen Yao
Keyword(s):  
Hydrogen Storage ◽  
Density Functional ◽  
Hydrogen Molecule ◽  
Hydrogen Adsorption ◽  
Density Functional Theory Calculations ◽  
Hydrogen Storage Material ◽  
Storage Material ◽  
Promising Candidate ◽  
Functional Theory ◽  
Doped Graphene

The adsorption hydrogen molecule on intrinsic and Al-doped graphene was studied by density functional theory calculations. The results show that the intrinsic graphene is not an ideal hydrogen storage material. Compared with the intrinsic, H2 molecules are stongly adsorbed onto the Al-doped graphene with higher adsorbed energy and shorter distance between H2 and surface. The band structure and density of states results show that between hydrogen and other atoms, the charge transfers are apparent increased. All are help for hydrogen adsorption. Therefore, Al-doped graphene is a promising candidate for hydrogen storage material.

Oxygen adsorption properties of small cobalt oxide clusters: application feasibility as oxygen gas sensors

2020 ◽  
Vol 22 (26) ◽  
pp. 14889-14899
Author(s):  
R. Molavi ◽  
R. Safaiee ◽  
M. H. Sheikhi
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Cobalt Oxide ◽  
Gas Sensors ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Oxygen Adsorption ◽  
Adsorption Properties ◽  
Functional Theory ◽  
Oxygen Gas

Density functional theory calculations show chemical exothermic oxygen adsorption on cobalt oxide clusters with charge transfer from the clusters to oxygen.

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