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The aggravation of the energy crisis makes it particularly important to develop catalysts that can efficiently enhance visible-light-catalyzed water splitting. We predict the potential of a type II van der Waals (vdW) g-ZnO/Ga2SSe heterostructure as an efficient photocatalyst based on density functional theory and analyze its optoelectronic and structural properties in this study. The results indicate that the g-ZnO/Ga2SSe heterostructure is a direct bandgap semiconductor, and the redistribution of charges on the layer interface will form a weak built-in electric field, which effectively inhibits the recombination of photon–hole pairs and improves the carrier mobility. More deeply, its suitable band gap and band edge positions can meet the requirements of water split oxidation and reduction reactions in the common pH range. This indicates that the g-ZnO/Ga2SSe vdW heterostructure has great potential to become an efficient photocatalyst for water splitting, which can provide a certain basis for the development of novel visible light-catalyzed water splitting catalysts. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysts are hampered by carriers' recombination problems that hinder their practical application. The rational design of direct Z-scheme heterojunctions based on two-dimensional (2D) materials is one of the effective ways to solve this problem. Therefore, we predicted 2D CrS2/boron phosphide (BP) van der Waals heterojunction as a potential direct Z-scheme photocatalyst based on density functional theory. The CrS2/BP heterojunction has a small direct band gap, which is favorable for light absorption. In addition, the built-in electric field promotes the separation and transfer of the desired carriers. Photogenerated electrons and holes are localized in the conduction band of the BP component and the valence band of the CrS2 component, respectively. In addition, it was found that the heterojunction obtained a relatively small band gap and a wide optical absorption range at + 4% and + 5% strains. Therefore, the CrS2/BP heterojunction is a new photocatalyst satisfying the direct Z-scheme charge transfer mechanism, which has a certain application value. [ABSTRACT FROM AUTHOR]

In the field of photocatalytic water splitting, the direct Z-scheme heterostructure is regarded as a promising photocatalyst configuration. In this paper, we use density functional theory to predict the Ti2CO2/CrSSe heterostructure as a potential direct Z-scheme heterojunction photocatalyst and investigate its electronic, optical, and heterojunction interface properties. The results show that the Ti2CO2/CrSSe heterojunction has a strong electrostatic attraction between the electrons in the conduction band of Ti2CO2 and the holes in the valence band of CrSSe due to the small interlayer band gap, which can realize the rapid interlayer electron-hole (e−–h+) recombination. The redistribution of charge results in a built-in electric field that prevents unwanted electron and hole migration. In addition, the Ti2CO2/CrSSe van der Waals (vdW) heterojunction exhibits excellent light absorption, and its redox ability has been improved. These properties indicate that Ti2CO2/CrSSe heterostructure is a promising photocatalyst. [ABSTRACT FROM AUTHOR]

Direct Z-scheme based on biomimetic artificial photosynthesis is a promising strategy to enhance photocatalytic activity. The search for direct Z-scheme photocatalysts is imperative, and the photocatalytic efficiency is mainly influenced by the separation rate of photogenerated electron–hole (e--h+) pairs and the light capture ability. Herein, a two-dimensional (2D) van der Waals (vdW) heterostructure consisting of a monolayer of CrS2 and Sc2CF2 is predicted based on density functional theory (DFT) as a promising direct Z-scheme photocatalyst for water splitting. The CrS2/Sc2CF2 heterojunction possesses a large energy band interleaving arrangement and a small interlayer band gap, and the orientation of the built-in electric field promotes interlayer carrier complexes, with electrons and holes localized at the highest redox energy level, respectively. In addition, the CrS2/Sc2CF2 heterojunction possesses a high overpotential driving force and excellent light harvest ability. Our calculations indicate that the CrS2/Sc2CF2 heterojunction is a promising new photocatalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • WSeTe/XS 2 (X = Hf, Sn, Zr) heterojunctions have direct Z-scheme band alignment and satisfy overall water splitting. • It has a high light absorption capacity and a wide light absorption range. • Photo-generated carriers interlayer recombine under the action of the built-in electric field. • Under the action of the vertical intrinsic electric field, the redox capacity is further improved. Finding photocatalytic materials with high hydrogen production efficiency is an effective way to solve the problem of the energy crisis. We use density functional theory (DFT) to predict the 2D WSeTe/XS 2 (X = Hf, Sn, Zr) van der Waals (vdW) heterojunctions as the potential direct Z-scheme heterojunction photocatalysts and discuss the mechanism of photocatalytic water splitting under the interaction of vertical intrinsic electric field and built-in electric field. The WSeTe/XS 2 heterojunctions have large band-edge staggered alignment, small interlayer bandgap, and good interlayer carrier recombination, which predict the direct Z-scheme charge transfer path formation. Meanwhile, the small bandgap of the 2D WSeTe/XS 2 direct Z-scheme heterojunctions enables it to obtain a wide light absorption range. The built-in electric field from WSeTe to XS 2 changes the charge transfer mode of the heterojunction and improves the separation efficiency of photo-generated carriers, and the vertical intrinsic electric field not only improves the hydrogen evolution reaction (HER) ability but also reduces the bandgap limitation of photocatalytic materials. In this paper, the 2D WSeTe/XS 2 heterojunctions show significant advantages as photocatalytic materials, providing unique insights for researching and developing this kind of heterojunction. [ABSTRACT FROM AUTHOR]

The two-dimensional MoSSe based heterostructures has attracted much attention due to its excellent physical and chemical properties. In this research, first principles study were used to investigate the stability, electronic structure and optical behavior of g-SiC/MoSSe vdW heterostructures, as well as the photocatalytic performance of the overall water splitting. This research found that the g-SiC/MoSSe vdW heterostructures was an indirect band gap semiconductor with a type II band alignment which indicated the reduction and oxidation reactions of water splitting were carried out in different layers. In addition, the 6.23 eV potential drop generated by the charges transfer in the interface region can effectively inhibit the photo-generated e−/h+ recombination which is beneficial to improve the carriers mobility and the existence lifetime. Significantly, the g-SiC/MoSSe vdW heterostructures has a relatively high optical absorption in the visible light region which can effectively utilize the solar energy comparing to g-SiC and MoSSe monolayers. At different pH of medium, the photocatalytic ability of g-SiC/MoSSe vdW heterostructures all satisfy the splitting of water. These fascinating properties indicate that g-SiC/MoSSe vdW heterostructures can be used as an efficient photocatalysts and have extraordinary application prospects. • The phonon spectrum, formation energy and AIMD simulation of the g-SiC/MoSSe vdWs heterostructures were calculated to ensure the reasonableness of subsequent calculations. • Using HSE06 hybrid functional to get the more accurate band gap value. • The light absorption coefficient of g-SiC/MoSSe vdWHs in the visible light is significantly improved. • The band edge positions alignment with different pH has been calculated. [ABSTRACT FROM AUTHOR]