scholarly journals On topological materials as photocatalysts for water splitting by visible light

2021 ◽  
Author(s):  
Ahmad Ranjbar ◽  
Hossein Mirhosseini ◽  
Thomas D Küehne
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Water Oxidation ◽  
Electronic Structures ◽  
Density Functional ◽  
Band Edge ◽  
Hybrid Functional ◽  
Functional Theory ◽  
Hartree Fock ◽  
Topological Materials

Abstract We performed virtual materials screening to identify promising topological materials for photocatalytic water splitting under visible light irradiation. Topological compounds were screened based on band gap, band edge energy, and thermodynamics stability criteria. In addition, topological types for our final candidates were computed based on electronic structures calculated by means of hybrid density functional theory including exact Hartree-Fock exchange. Our final list contains materials which have band gaps between 1.0 eV and 2.7 eV in addition to band edge energies suitable for water oxidation and reduction. However, the topological types of these compounds calculated with the hybrid functional differ from those reported previously. To that end, we discuss the importance of computational methods for the calculation of atomic and electronic structures in materials screening processes.

First-principles study on codoping effect to enhance photocatalytic activity of anatase TiO2

2017 ◽  
Vol 31 (06) ◽  
pp. 1750036
Author(s):  
Yujie Bai ◽  
Qinfang Zhang ◽  
Fubao Zheng ◽  
Yun Yang ◽  
Qiangqiang Meng ◽  
...  
Keyword(s):  
Visible Light ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Theory Calculations ◽  
Band Edge ◽  
Electron Hole ◽  
Functional Theory ◽  
Rich Condition

Codopant is an effective approach to modify the bandgap and band edge positions of transition metal oxide. Here, the electronic structures as well as the optical properties of pristine, mono-doped (N/P/Sb) and codoped (Sb, N/P) anatase TiO2 have been systematically investigated based on density functional theory calculations. It is found that mono-doped TiO2 exhibits either unoccupied or partially occupied intermediate state within the energy gap, which promotes the recombination of electron-hole pairs. However, the presence of (Sb, N/P) codopant not only effectively reduces the width of bandgap by introducing delocalized occupied intermediate states, but also adjusts the band edge alignment to enhance the hydrogen evolution activity of TiO2. Moreover, the optical absorption spectrum for (Sb, N/P) codoped TiO2, which is favored under oxygen-rich condition, demonstrates the improvement of its visible light absorption. These findings will promote the potential application of (Sb, N/P) codoped TiO2 photocatalysis for water splitting under visible light irradiation.

Novel visible-light sensitive vanadate photocatalysts for water oxidation: implications from density functional theory calculations

2015 ◽  
Vol 3 (20) ◽  
pp. 10720-10723 ◽  
Author(s):  
Peng Li ◽  
Naoto Umezawa ◽  
Hideki Abe ◽  
Jinhua Ye
Keyword(s):  
Density Functional Theory ◽  
Visible Light ◽  
Water Oxidation ◽  
Electronic Structures ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Oxidation Reactions ◽  
Functional Theory

New vanadate photocatalysts, Ag2Sr(VO3)4 and Sr(VO3)2, are theoretically designed for water oxidation reactions. The calculations have shown that the new photocatalysts possess desirable electronic structures. Our experiments demonstrated that these vanadates efficiently oxidize water to O2 under irradiation of visible light.

Tunable electronic properties of GaS-SnS2 heterostructure by strain and electric field

2021 ◽  
Author(s):  
Dahua Ren ◽  
Qiang Li ◽  
Kai Qian ◽  
Xingyi Tan
Keyword(s):  
Optical Properties ◽  
Electric Field ◽  
Visible Light ◽  
Electronic Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Band Alignment ◽  
Promising Candidate ◽  
Functional Theory ◽  
External Strain

Abstract Vertically stacked heterostructures have received extensive attention because of their tunable electronic structures and outstanding optical properties. In this work, we have studied the structural, electronic and optical properties of vertically stacked GaS-SnS2 heterostructure under the frame of density functional theory. We find that the stacked GaS-SnS2 heterostructure is a semiconductor with suitable indirect band gaps of 1.82 eV, exhibiting a type-II band alignment for easily separating the photo-generated carriers. The electronic properties of GaS-SnS2 heterostructure can be effectively tuned by external strain and electric field. The optical absorption of GaS-SnS2 heterostructure is more enhanced by comparison with the GaS monolayer and SnS2 monolayer in the visible light. Our results suggest that GaS-SnS2 heterostructure is a promising candidate for the photocatalyst and photoelectronic devices in visible light.

scholarly journals Bilayer MoSe2/HfS2 Nanocomposite as a Potential Visible-Light-Driven Z-Scheme Photocatalyst

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1706 ◽  
Author(s):  
Biao Wang ◽  
Xiaotian Wang ◽  
Peng Wang ◽  
Tie Yang ◽  
Hongkuan Yuan ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Density Functional ◽  
Infrared Region ◽  
Internal Electric Field ◽  
Functional Theory ◽  
Overall Water Splitting ◽  
Visible Light Driven ◽  
Electron Migration ◽  
Redox Ability

Visible-light-driven photocatalytic overall water splitting is deemed to be an ideal way to generate clean and renewable energy. The direct Z-scheme photocatalytic systems, which can realize the effective separation of photoinduced carriers and possess outstanding redox ability, have attracted a huge amount of interest. In this work, we have studied the photocatalytic performance of the bilayer MoSe2/HfS2 van der Waals (vdW) heterojunction following the direct Z-scheme mechanism by employing the hybrid density functional theory. Our calculated results show that the HfS2 and MoSe2 single layers in this heterojunction are used for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. The charge transfer between the two layers brought about an internal electric field pointing from the MoSe2 layer to the HfS2 slab, which can accelerate the separation of the photoinduced electron–hole pairs and support the Z-scheme electron migration near the interface. Excitingly, the optical absorption intensity of the MoSe2/HfS2 heterojunction is enhanced in the visible and infrared region. As a result, these results reveal that the MoSe2/HfS2 heterojunction is a promising direct Z-scheme photocatalyst for photocatalytic overall water splitting.

scholarly journals Designing an active Ta3N5 photocatalyst for H2 and O2 evolution reactions by specific exposed facet engineering: a first-principles study

2020 ◽  
Vol 22 (18) ◽  
pp. 10295-10304 ◽  
Author(s):  
Moussab Harb ◽  
Luigi Cavallo ◽  
Jean-Marie Basset
Keyword(s):  
Density Functional Theory ◽  
Water Splitting ◽  
First Principles ◽  
Density Functional ◽  
O2 Evolution ◽  
Hybrid Functional ◽  
Functional Theory ◽  
Native Defects ◽  
Exposed Facet ◽  
Exposed Facets

The effects of native defects and exposed facets on the thermodynamic stability and photocatalytic characteristics of Ta3N5 for water splitting are studied by applying accurate quantum computations on the basis of density functional theory (DFT) with the range-separated hybrid functional (HSE06).

scholarly journals Фотонный спектр Eu-=SUB=-2-=/SUB=-Sn-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=-: ab initio расчет

2020 ◽  
Vol 128 (11) ◽  
pp. 1668
Author(s):  
В.А. Чернышев ◽  
П.А. Агзамова ◽  
А.В. Архипов
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Vibrational Mode ◽  
Periodic Structures ◽  
Hybrid Functional ◽  
Fundamental Vibration ◽  
Functional Theory ◽  
Hartree Fock ◽  
Displacement Vectors ◽  
Lcao Approximation

Crystal structure and phonon spectrum of crystal Eu2Sn2O7 were studied within the framework of density functional theory and MO LCAO approach. The calculations were performed by using hybrid functional that takes into account both local and nonlocal (in the Hartree–Fock formalism) exchange. The calculations were performed in the CRYSTAL17 program intended for simulating periodic structures in the MO LCAO approximation. The fundamental vibration frequencies of Eu2Sn2O7 were calculated. The frequencies, intensities and types of the Raman and the IR-active modes have been calculated. An analysis of the displacement vectors obtained from the ab initio calculation, made it possible to estimate the degree of the ion participation in the vibrational mode. The elastic constants of the crystal have been calculated too.

(Cu, Ag)-DOPED ZnS WITH WIDE VISIBLE LIGHT RANGE ABSORPTION FOR WATER SPLITTING: A THEORETICAL AND EXPERIMENTAL STUDY

2019 ◽  
Vol 27 (04) ◽  
pp. 1950139
Author(s):  
XIAOBO CHEN ◽  
WEIWEI LIU ◽  
ZHIHAI ZHANG ◽  
WEN YANG ◽  
PEIZHI YANG
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Density Functional ◽  
Energy Levels ◽  
Experimental Studies ◽  
Density Functional Theory Calculations ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Functional Theory ◽  
Light Region

Photocatalytic water splitting using a semiconductor photocatalyst is a promising process for direct solar energy conversion. In this study, the feasibility of the photocatalytic H2 evolution on (Cu, Ag)- doped ZnS catalysts under visible light irradiation has been investigated by using first-principles density functional theory calculations and experimental studies. The present results reveal that (Cu, Ag)-doped ZnS structures have relatively small formation energy, implying that they are more easily obtained in experiment. Moreover, the absorption is enhanced obviously in the visible-light region for (Cu, Ag)-doped ZnS, but their energy levels are still suitable for water splitting to generate H2, which means that (Cu, Ag)-doped ZnS structures are promising candidate photocatalyst materials for H2 production driven by visible light. ZnS and (Cu, Ag)-doped ZnS were prepared using chemical precipitation method. (Cu, Ag)-doped ZnS samples showed an improved photocatalytic activity compared with undoped ZnS. Ag-doped ZnS (0.15 g L[Formula: see text] has the highest hydrogen evolution rate of 794.6 [Formula: see text]mol[Formula: see text] h[Formula: see text] [Formula: see text] g[Formula: see text] at pH 3 (0.1 M Na2S solution as a sacrificing agent).

scholarly journals Two dimensional ZnO/AlN composites used for photocatalytic water-splitting: a hybrid density functional study

RSC Advances ◽  
2019 ◽  
Vol 9 (62) ◽  
pp. 36234-36239 ◽  
Author(s):  
Guangzhao Wang ◽  
Yumo Li ◽  
Ling Zhang ◽  
Junli Chang ◽  
Yadong Li ◽  
...  
Keyword(s):  
Electric Field ◽  
Visible Light ◽  
Water Splitting ◽  
Density Functional ◽  
Band Edge ◽  
Functional Study ◽  
Two Dimensional ◽  
Carrier Recombination ◽  
Photoexcited Carrier ◽  
Hybrid Density Functional

With adapted bandgap for absorbing visible light, suitable band edge positions, and induced electric field inhibiting photoexcited carrier recombination, 2% strained ZnO/AlN composite is a promising water-splitting photocatalyst.

scholarly journals Cтруктура и динамика решетки кристаллов Nd-=SUB=-2-=/SUB=-TiO-=SUB=-5-=/SUB=- и Sm-=SUB=-2-=/SUB=-TiO-=SUB=-5-=/SUB=-: ab initio расчет

2019 ◽  
Vol 61 (6) ◽  
pp. 1151
Author(s):  
В.А. Чернышев ◽  
В.С. Рюмшин
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Vibration Frequencies ◽  
Hybrid Functional ◽  
Fundamental Vibration ◽  
Functional Theory ◽  
Lattice Constants ◽  
Hartree Fock ◽  
Phonon Spectra ◽  
First Time

Crystal structure and phonon spectra R2TiO5 (R = Nd, Sm) were studied within the framework of density functional theory and MO LKAO approach. The calculations were performed by using hybrid functional that takes into account both local and nonlocal (at the Hartree-Fock formalism) exchange. The coordinates of the ions in the unit cell and the lattice constants are calculated. The fundamental vibration frequencies of R2TiO5 (R = Nd, Sm) were calculated. The relative intensities of the Raman lines and the intensity of the IR-active modes have been calculated. The elastic constants of the crystal have been calculated at the first time.

Sign in / Sign up

Export Citation Format

Share Document