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 Modification of TiO2 with Metal Chalcogenide Nanoclusters for Hydrogen Evolution

2020 ◽  
Author(s):  
Stephen Rhatigan ◽  
Lorenzo Niemitz ◽  
Michael Nolan
Keyword(s):  
Density Functional Theory ◽  
Surface Modification ◽  
Hydrogen Evolution ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Coulomb Interactions ◽  
Free Energies ◽  
Functional Theory ◽  
Metal Chalcogenide ◽  
Adsorption Energies

Using density functional theory, corrected for on-site Coulomb interactions (DFT+U), we have investigated surface modification of TiO<sub>2</sub> with metal chalcogenide nanoclusters for hydrogen evolution. The nanoclusters have composition M<sub>4</sub>X<sub>4</sub> (M = Sn, Zn; X = S, Se) and are adsorbed at the rutile (110) surface. The nanoclusters adsorb exothermically, with adsorption energies in the range -3.00 eV to -2.70 eV. Computed density of states (DOS) plots show that cluster-derived states extend into the band-gap of the rutile support, which indicates that modification produces a redshift in light absorption. After modification, photoexcited electrons and holes are separated onto surface and cluster sites, respectively. The free energy of H adsorption is used to assess the performance of metal chalcogenide modified TiO<sub>2</sub> as a catalyst for HER. Adsorption of H at nanocluster (S, Se) and surface (O) sites is considered, together with the effect of H coverage. Adsorption free energies at cluster sites in the range (-0.15 eV, 0.15 eV) are considered to be favourable for HER. The results of this analysis indicate that the sulphide modifiers are more active towards HER than the selenide modifiers and exhibit hydrogen adsorption free energies in the active range, for most coverages. Conversely, the adsorption free energies at the selenide nanoclusters are only in the active range at low H coverages. Our results indicate that surface modification with small, dispersed nanoclusters of appropriately selected materials can enhance the photocatalytic activity of TiO<sub>2</sub> for HER applications.

scholarly journals Modification of TiO2 with Metal Chalcogenide Nanoclusters for Hydrogen Evolution

2020 ◽  
Author(s):  
Stephen Rhatigan ◽  
Lorenzo Niemitz ◽  
Michael Nolan
Keyword(s):  
Density Functional Theory ◽  
Surface Modification ◽  
Hydrogen Evolution ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Coulomb Interactions ◽  
Free Energies ◽  
Functional Theory ◽  
Metal Chalcogenide ◽  
Adsorption Energies

Using density functional theory, corrected for on-site Coulomb interactions (DFT+U), we have investigated surface modification of TiO<sub>2</sub> with metal chalcogenide nanoclusters for hydrogen evolution. The nanoclusters have composition M<sub>4</sub>X<sub>4</sub> (M = Sn, Zn; X = S, Se) and are adsorbed at the rutile (110) surface. The nanoclusters adsorb exothermically, with adsorption energies in the range -3.00 eV to -2.70 eV. Computed density of states (DOS) plots show that cluster-derived states extend into the band-gap of the rutile support, which indicates that modification produces a redshift in light absorption. After modification, photoexcited electrons and holes are separated onto surface and cluster sites, respectively. The free energy of H adsorption is used to assess the performance of metal chalcogenide modified TiO<sub>2</sub> as a catalyst for HER. Adsorption of H at nanocluster (S, Se) and surface (O) sites is considered, together with the effect of H coverage. Adsorption free energies at cluster sites in the range (-0.15 eV, 0.15 eV) are considered to be favourable for HER. The results of this analysis indicate that the sulphide modifiers are more active towards HER than the selenide modifiers and exhibit hydrogen adsorption free energies in the active range, for most coverages. Conversely, the adsorption free energies at the selenide nanoclusters are only in the active range at low H coverages. Our results indicate that surface modification with small, dispersed nanoclusters of appropriately selected materials can enhance the photocatalytic activity of TiO<sub>2</sub> for HER applications.

Identifying the catalytically active sites on the layered tri-chalcogenide compounds CoPS3 and NiPS3 for efficient hydrogen evolution reaction

2021 ◽  
Author(s):  
Khorsed Alam ◽  
Tisita Das ◽  
Sudip Chakraborty ◽  
Prasenjit Sen
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Density Functional ◽  
Electronic Structure Calculations ◽  
Functional Theory ◽  
Catalytically Active ◽  
Structure Calculations

Electronic structure calculations based on density functional theory are used to identify the catalytically active sites for the hydrogen evolution reaction on single layers of the two transition metal tri-chalcogenide...

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 Predicted polymorph manipulation in an exotic double perovskite oxide

2019 ◽  
Vol 7 (39) ◽  
pp. 12306-12311 ◽  
Author(s):  
He-Ping Su ◽  
Shu-Fang Li ◽  
Yifeng Han ◽  
Mei-Xia Wu ◽  
Churen Gui ◽  
...  
Keyword(s):  
Phase Transition ◽  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Double Perovskite ◽  
Density Functional Theory Calculations ◽  
Perovskite Oxide ◽  
Functional Theory ◽  
First Time ◽  
Perovskite Type

First-principles density functional theory calculations, for the first time, was used to predict the Mg3TeO6-to-perovskite type phase transition in Mn3TeO6 at around 5 GPa.

Two dimensional MoS2 meets porphyrins via intercalation to enhance the electrocatalytic activity toward hydrogen evolution

Nanoscale ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 3780-3785 ◽  
Author(s):  
Ik Seon Kwon ◽  
In Hye Kwak ◽  
Hafiz Ghulam Abbas ◽  
Hee Won Seo ◽  
Jaemin Seo ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Electrocatalytic Activity ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Two Dimensional ◽  
Functional Theory ◽  
Spin Polarized

Mn-Porphyrin-MoS2 exhibits excellent electrocatalytic activity toward the hydrogen evolution reaction, which is supported by spin-polarized density functional theory calculations.

scholarly journals Electronic Structure of the Aqueous Vanadyl Ion Probed by 9 and 94 GHz EPR and Pulsed ENDOR Spectroscopies and Density Functional Theory Calculations

1999 ◽  
Vol 103 (48) ◽  
pp. 10627-10631 ◽  
Author(s):  
Christopher V. Grant ◽  
William Cope ◽  
James A. Ball ◽  
Guenter G. Maresch ◽  
Betty J. Gaffney ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Vanadyl Ion

Intercalation of cobaltocene into WS2 nanosheets for enhanced catalytic hydrogen evolution reaction

2019 ◽  
Vol 7 (14) ◽  
pp. 8101-8106 ◽  
Author(s):  
In Hye Kwak ◽  
Hafiz Ghulam Abbas ◽  
Ik Seon Kwon ◽  
Yun Chang Park ◽  
Jaemin Seo ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Spin Polarized ◽  
Catalytic Hydrogen ◽  
Catalytic Hydrogen Evolution ◽  
Ws2 Nanosheets

Cobaltocene-intercalated WS2 nanosheets exhibit excellent catalytic activity toward the hydrogen evolution reaction, which is supported by spin-polarized density functional theory calculations.

Tuning the electronic structure properties of MoS2 monolayers with carbon doping

2019 ◽  
Vol 21 (21) ◽  
pp. 11168-11174 ◽  
Author(s):  
Wiliam Ferreira da Cunha ◽  
Ramiro Marcelo dos Santos ◽  
Rafael Timóteo de Sousa Júnior ◽  
Renato Batista Santos ◽  
Geraldo Magela e Silva ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Electronic Properties ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Carbon Doping ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Mos2 Monolayers ◽  
Structure Properties

The structural and electronic properties of MoS2 sheets doped with carbon line domains are theoretically investigated through density functional theory calculations.

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