Enhancing the photocatalytic hydrogen generation performance and strain regulation of the vertical GeI₂/C₂N van der Waals heterostructure: insights from first-principles study

Abstract

A suitable electronic structure and efficient charge separation are significant for the performance of photocatalytic water splitting. Herein, we have designed a two-dimensional GeI2/C2N van der Waal (vdW) heterostructure and...

Effect of van der Waals stacking in CdS monolayer on enhancing the hydrogen production efficiency of SiH monolayer

“…Several studies have been undertaken since the discovery of graphene to examine potential two-dimensional (2D) photocatalysts for water splitting, 12–14 such as MXenes, Janus MAB (M = Mo and W; A and B = S, Se and Te), graphitic carbon nitrides (g-C 6 N 6 , g-C 3 N 4 and C 2 N), group-III (IV) monochalcogenides, boron nitride, and transition-metal dichalcogenides. 15–18 Due to their exceptional chemical and physical properties, as well as their great performances in a variety of applications, 2D materials have recently attracted widespread attention.…”

“…7,8 Photocatalysis technology is one of the most promising routes to address environmental problems, 9 which has several benefits compared to other solutions, such as high efficiency, environmental protection, direct use of sunlight at room temperature and good selectivity. 10,11 Several studies have been undertaken since the discovery of graphene to examine potential two-dimensional (2D) photocatalysts for water splitting, [12][13][14] such as MXenes, Janus MAB (M = Mo and W; A and B = S, Se and Te), graphitic carbon nitrides (g-C 6 N 6 , g-C 3 N 4 and C 2 N), group-III (IV) monochalcogenides, boron nitride, and transition-metal dichalcogenides. [15][16][17][18] Due to their exceptional chemical and physical properties, as well as their great performances in a variety of applications, 2D materials have recently attracted widespread attention.…”

Promoted photocarrier separation by dipole engineering in two-dimensional perovskite/C2N van der Waals heterostructures

“…The electric field has little effect on the absorption spectrum, and the absorption coefficient decreases slightly regardless of the positive or negative electric field. On comparing with the previously reported type-II semiconductor heterostructures, 70,85,89 the isolated Cs 3 Bi 2 I 9 has five atomic layers. Therefore, in the process of applying in-plane strain or changing interface spacing, the system has a certain buffer effect on these external disturbances.…”

“…To evaluate the relative stability of the heterostructure, the interface binding energy (E b ) is calculated, according to the equation E b = (E HS À E CsBiI À E CN )/S, where E HS is the total energy of the heterostructure, E CsBiI and E CN are, respectively, the energies of Cs 3 Bi 2 I 9 and C 2 N monolayers fixed with the same lattice constant as the heterostructure, and S denotes the contact area. The calculated binding energy of Cs 3 Bi 2 I 9 /C 2 N is À65.84 meV Å À2 , which is more negative than those of other C 2 N-based heterostructures, such as GeI 2 /C 2 N (À14.94 meV Å À2 ), 70 h-BN/C 2 N (À13.40 meV Å À2 ), 29 g-ZnO/C 2 N (À44.29 meV Å À2 ), 71 and blueP/ C 2 N (À42.01 meV Å À2 ), 42 indicating that the Cs 3 Bi 2 I 9 /C 2 N heterostructure should possess better stability. Moreover, the negative binding energy corresponds to an exothermic reaction, which further confirms the thermodynamic feasibility.…”

“…The lattice mismatch is determined by the relation η = 2( a 1 − a 2 )/( a 1 + a 2 ) × 100%, which shows that there is a slight mismatch of 3.19% occurring in the vdW heterostructure, ensuring the structural stability and experimental feasibility. 70 In our theoretical simulation, the lattice constants of the heterostructure are first sited to the average value due to the absence of a substrate, where moderate strains are applied to both the monolayers. During atomic structure relaxation calculations to find the most energetically favorable structure, all the atoms and in-plane lattice vectors of the simulation box are free to relax.…”