Two-dimensional SiC/AlN based type-II van der Waals heterobilayer as a promising photocatalyst for overall water disassociation

Abstract

Two-dimensional (2D) van der Waals (vdW) heterostructures made by vertical assembling of two different layers have drawn immense attention in the photocatalytic water disassociation process. Herein, we suggest a novel 2D/2D vdW heterobilayer consisting of silicon carbide (SiC) and aluminum nitride (AlN) as an exciting photocatalyst for solar-to-hydrogen conversion reactions using first-principles calculations. Notably, the heterostructure presents an inherent type-II band orientation wherein the photogenic holes and electrons are spatially separated in the SiC layer and the AlN layer, respectively. Our results indicate that the SiC/AlN heterostructure occupies a suitable band-gap of 2.97 eV which straddles the kinetic overpotentials of the hydrogen production reaction and oxygen production reaction. Importantly, the built-in electric field at the interface created by substantial charge transfer prohibits carrier recombination and further improves the photocatalytic performance. The heterostructure has an ample absorption profile ranging from the ultraviolet to the near-infrared regime, while the intensity of the absorption reaches up to 2.16 × 105 cm−1. In addition, external strain modulates the optical absorption of the heterostructure effectively. This work provides an intriguing insight into the important features of the SiC/AlN heterostructure and renders useful information on the experimental design of a novel vdW heterostructure for solar energy-driven water disassociation with superior efficiency.

Identifying hexagonal 2D planar electrocatalysts with strong OCHO* binding for selective CO2 reduction

“…The optimized lattice constants of monolayers AlN, GaN, InN, SiC, GeC, and SnC are 3.13, 3.19, 3.62, 3.10, 3.25, and 3.61 Å, respectively, which are consistent with the values reported in the literature. 57–63 Herein, we construct a 5 × 5 supercell as the base (Fig. 1, middle column) to absorb intermediates and found that H*, O*, and HO* intermediates tend to absorb at the T1 site of AlN, InN, and SnC, while for SiC : O* at T1, H* and HO* on T2; for GeC : HO* on T2, H* and O* on T1; for GaN : H* on T2, O* and HO* on T1.…”

“…The optimized lattice constants of monolayers AlN, GaN, InN, SiC, GeC, and SnC are 3.13, 3.19, 3.62, 3.10, 3.25, and 3.61 Å, respectively, which are consistent with the values reported in the literature. [57][58][59][60][61][62][63] Herein, we construct a 5 × 5 supercell as the base (Fig. Identifying the catalytic sites forms the cornerstone of unearthing the reaction reactivity.…”

Growth mechanisms of monolayer hexagonal boron nitride (h-BN) on metal surfaces: theoretical perspectives

“…In the last decade, several scientific breakthroughs have been made in two-dimensional (2D) materials, 1–5 including graphene, 6–19 hexagonal boron nitride ( h -BN), 20–48 transition-metal dichalcogenides (TMDCs), 49–66 layered double hydroxides (LDHs), 67–74 metal–organic frameworks (MOFs), 75–79 black phosphorus (BP), 80–87 and so many others. 88–116 In particular, 2D h -BN, a geometrical analogue to graphene, is extensively studied due to its distinctive chemical and physical features. Despite the possibility that the lattice characteristics of h -BN are identical to those of carbon, the distinct constituent components give it highly diverse physical properties.…”

Type-II 2D AgBr/SiH van der Waals heterostructures with tunable band edge positions and enhanced optical absorption coefficients for photocatalytic water splitting

“…In addition, applying strain on heterostructures has been a commonly used method for manipu-lating their optoelectronic characteristics. Prior studies have established that strain engineering can induce changes in the bandgap, [53][54][55] relocation of the band edge, 56 enhancement of the optical absorption coefficient, [57][58][59] and ad-justment of the band alignment of the hetero-structures. 60 To gain a complete understanding of the geometry, electronic and optical properties of AgBr/SiH vdW heterojunctions and how these properties are affected by strain, further research is needed as the current knowledge on this topic is limited.…”

“…In addition, applying strain on heterostructures has been a commonly used method for manipu-lating their optoelectronic characteristics. Prior studies have established that strain engineering can induce changes in the bandgap, 53–55 relocation of the band edge, 56 enhancement of the optical absorption coefficient, 57–59 and ad-justment of the band alignment of the hetero-structures. 60…”