Inartificial Two-Dimensional Ge<sub>4</sub>Se<sub>9</sub> Janus Structures with Appropriate Direct Band Gaps and Intrinsic Polarization Boosted Charge Separation for Photocatalytic Water Splitting

Zhou, Yungang; Zhou, Liujiang; He, Junjie; Frauenheim, Thomas

doi:10.1021/acs.jpclett.0c00190

Cited by 32 publications

(23 citation statements)

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“…Another important feature of the present single/double halogen layer system can be found in the spatial separation of the CBM and VBM, which is regarded as an effective strategy to promote charge separation. − Figure a,b shows the orbital distributions of PbBi 3 O 4 Cl 3 , in which the orbital distribution of CBM spread over the single halogen layer side (mainly on Bi cations) whereas that of VBM is found over the double halogen side (mainly on Pb cations and O and Cl anions). Such a spatial separation based on the asymmetry of halogen layers is unavailable in conventional oxyhalides consisting either of the double halogen layers (BiOCl) or single ones (PbBiO 2 Cl), probably affording the present PbBi 3 O 4 X 3 system a higher efficiency in charge separation.…”

Section: Resultsmentioning

confidence: 99%

PbBi₃O₄X₃ (X = Cl, Br) with Single/Double Halogen Layers as a Photocatalyst for Visible-Light-Driven Water Splitting: Impact of a Halogen Layer on the Band Structure and Stability

et al. 2021

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Layered oxyhalides with a Silleń(−Aurivillius) structure have attracted considerable attention as promising photocatalysts for efficient visible-light-induced water splitting due to the elevation of the O-2p valence band maximum (VBM) derived from the strong s−p interaction between Pb/Bi-6s and O-2p electrons and the electrostatic destabilization of oxygen anions in the fluorite layers. However, the role of the halogen layer, consisting of single or double layers, was not known. In this study, we examined a Silleń-type layered oxyhalide PbBi 3 O 4 X 3 (X = Cl, Br) with alternating stacks of single/double halogen layers and skeletal Bi-based oxide layers. Density functional theory (DFT) calculations of PbBi 3 O 4 X 3 revealed that the two inequivalent halogen layers contribute differently to the valence band density of states; the halogen p orbitals in double layers are higher in energy and responsible for the VBM, which is understood in terms of Madelung site potentials, where the electrostatic repulsion between halide ions is at play. Another finding from the DFT calculation is the spatial separation of the conduction band minimum and the VBM based on the asymmetry of halogen layers, which may promote the charge separation. While both PbBi 3 O 4 Cl 3 and PbBi 3 O 4 Br 3 possess band levels appropriate for visible-light-induced water splitting, only the former showed photocatalytic O 2 evolution activity. The stability of PbBi 3 O 4 Cl 3 is due to the significant contribution of the O-2p orbitals to its VBM, in stark contrast to PbBi 3 O 4 Br 3 , where Br-4p predominately contributes to the VBM. PbBi 3 O 4 Cl 3 functions as a stable O 2 -evolving photocatalyst in Z-scheme water splitting under visible light irradiation. These results show that the electrostatic repulsion of halogen layers is a key factor for tuning the valence band structure of oxyhalides while maintaining sufficient stability for water-splitting photocatalysis.

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Section: Resultsmentioning

confidence: 99%

PbBi₃O₄X₃ (X = Cl, Br) with Single/Double Halogen Layers as a Photocatalyst for Visible-Light-Driven Water Splitting: Impact of a Halogen Layer on the Band Structure and Stability

et al. 2021

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“…68 Interestingly, all these NTs have a direct bandgap character with a moderate band gap value, suggesting that they have bright prospects for application in photoelectric devices, as electrons can be directly excited from the valence band maximum (VBM) to the conduction band minimum (CBM) by incident light with an appropriate frequency without the aid of phonons. 69 The atom-projected band structures show that the VBM is contributed by the outer anion (S or Se) while the CBM is composed of the hybridized states of Sn and S/Se. Due to its strong electronegativity, O forms deep energy states within the valence band, which are far from the Fermi level ( E F ).…”

Section: Resultsmentioning

confidence: 99%

Ultrahigh-stability SnOX (X = S, Se) nanotubes with a built-in electric field as a highly promising platform for sensing NH₃, NO and NO₂: a theoretical investigation

et al. 2022

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“…Our calculations are carried out within the density functional theory (DFT) , framework as implemented by the Vienna Ab initio Simulation Package (VASP) code. , The projected augmented-wave approach (PAW) pseudopotential , are used to describe the interaction between ions and electrons, and the electronic configurations for the PAW potentials are 3d 3 4s 1 for Ti, 4s 2 4p 6 4d 3 5s 1 for Zr, 5d 3 6s 1 for Hf, 4d 5 5s 1 for Mo, 4s 2 4p 6 4d 4 5s 1 for Nb and 1s 1 for H. The exchange-correlation effects are treated by the local-density approximation (LDA) in the Ceperley-Alder parametrization . All the calculations are conducted using a supercell consisting of 100 atoms, with a 2 × 2 x 2 Monkhorst–Pack k-mesh for Brillouin-zone integrations and a cutoff energy of 500 eV for the plane wave basis set.…”

Section: Computational Detailsmentioning

confidence: 99%

A Density Functional Theory Study of the Hydrogen Absorption in High Entropy Alloy TiZrHfMoNb

Zhang

Xiao

et al. 2020

Inorg. Chem.

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The high entropy alloy is promising for hydrogen storage, especially in regard to its adjustable hydrogen storage properties. Despite several experimental investigations, there still lacks a detailed atomic-level understanding of the hydrogenation process. In this study, based on first-principles calculations, the hydrogen behaviors and microstructural evolution in high entropy alloy TiZrHfMoNb during the hydrogen absorption are investigated systematically. At low hydrogen content, hydrogen atoms prefer to occupy the octahedral interstitial sites of the BCC phase, which is different from that in BCC pure metals; when the hydrogen content reaches 1.08 wt %, the BCC TiZrHfMoNb hydrides transform into FCC phase, and hydrogen atoms are more favorable to occupy the tetrahedral interstitial sites. Further radial distribution function (RDF) analysis indicates that the enhanced disorder of bonds and decreased lattice distortion of the metal structure destabilize the BCC TiZrHfMoNb hydride and eventually induce the BCC → FCC phase transformation, which is quite different from that in conventional alloys; the difference originates from the severe lattice distortion in high entropy alloy. The phonon spectra of different TiZrHfMoNb hydrides show that the hydride with a H/M ratio of 2 dynamically has a stable lattice, corresponding to a hydrogen storage capacity of 1.94 wt %. The present study demonstrates that the high entropy alloys have unique hydrogen absorption ability, which may advance the related experimental and theoretical studies.

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Inartificial Two-Dimensional Ge₄Se₉ Janus Structures with Appropriate Direct Band Gaps and Intrinsic Polarization Boosted Charge Separation for Photocatalytic Water Splitting

Cited by 32 publications

References 50 publications

PbBi₃O₄X₃ (X = Cl, Br) with Single/Double Halogen Layers as a Photocatalyst for Visible-Light-Driven Water Splitting: Impact of a Halogen Layer on the Band Structure and Stability

PbBi₃O₄X₃ (X = Cl, Br) with Single/Double Halogen Layers as a Photocatalyst for Visible-Light-Driven Water Splitting: Impact of a Halogen Layer on the Band Structure and Stability

Ultrahigh-stability SnOX (X = S, Se) nanotubes with a built-in electric field as a highly promising platform for sensing NH₃, NO and NO₂: a theoretical investigation

A Density Functional Theory Study of the Hydrogen Absorption in High Entropy Alloy TiZrHfMoNb

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Inartificial Two-Dimensional Ge4Se9 Janus Structures with Appropriate Direct Band Gaps and Intrinsic Polarization Boosted Charge Separation for Photocatalytic Water Splitting

Cited by 32 publications

References 50 publications

PbBi3O4X3 (X = Cl, Br) with Single/Double Halogen Layers as a Photocatalyst for Visible-Light-Driven Water Splitting: Impact of a Halogen Layer on the Band Structure and Stability

PbBi3O4X3 (X = Cl, Br) with Single/Double Halogen Layers as a Photocatalyst for Visible-Light-Driven Water Splitting: Impact of a Halogen Layer on the Band Structure and Stability

Ultrahigh-stability SnOX (X = S, Se) nanotubes with a built-in electric field as a highly promising platform for sensing NH3, NO and NO2: a theoretical investigation

A Density Functional Theory Study of the Hydrogen Absorption in High Entropy Alloy TiZrHfMoNb

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Inartificial Two-Dimensional Ge₄Se₉ Janus Structures with Appropriate Direct Band Gaps and Intrinsic Polarization Boosted Charge Separation for Photocatalytic Water Splitting

PbBi₃O₄X₃ (X = Cl, Br) with Single/Double Halogen Layers as a Photocatalyst for Visible-Light-Driven Water Splitting: Impact of a Halogen Layer on the Band Structure and Stability

PbBi₃O₄X₃ (X = Cl, Br) with Single/Double Halogen Layers as a Photocatalyst for Visible-Light-Driven Water Splitting: Impact of a Halogen Layer on the Band Structure and Stability

Ultrahigh-stability SnOX (X = S, Se) nanotubes with a built-in electric field as a highly promising platform for sensing NH₃, NO and NO₂: a theoretical investigation