A two-dimensional layered CdS/C₂N heterostructure for visible-light-driven photocatalysis

Abstract

In this work, we employ hybrid density functional theory calculations to design a two-dimensional layered CdS/CN heterostructure for visible light photocatalytic water splitting to produce hydrogen. The calculation results show that the conduction band minimum (CBM) and the valence band maximum (VBM) of CN monolayers are lower than those of CdS nanosheets by about 0.76 eV and 0.44 eV, respectively. The type-II band alignment, density of states, Bader charge analysis, and charge density difference of the CdS/CN heterostructure indicate that the photogenerated electrons migrate from the CdS monolayer to the CN monolayer, favoring the separation and transfer of photogenerated charge carriers, which restrains the recombination of photogenerated carriers and enhances the photocatalytic efficiency. The calculated band gap and optical absorption spectra reveal that the two-dimensional layered CdS/CN heterostructure may be a potential photocatalyst for photo-electrochemical water splitting because of its appropriate band gap and excellent visible light absorption behavior. Moreover, the electronic and optical properties of the CdS/CN heterostructure can be effectively modulated by the strain. These findings suggest that the CN sheets are a promising candidate as metal-free co-catalysts for CdS photocatalysts, and also provide valuable information for experimentalists to design highly active and efficient visible light photocatalysts for water splitting.

Rotation Tunable Photocatalytic Properties of ZnO/GaN Heterostructures

“…Combining two different semiconductors to construct a heterostructure is an effective strategy for enhancing photocatalytic performance, which should be attributed to the fact that the heterostructure usually has smaller bandgap than the single semiconductor, and the formation of the built‐in electric field in the heterostructure interface area can hinder photogenerated carriers. A series of heterostructures, such as C 2 N/InTe, AlN/WS 2 , MoTe 2 /CrS 2 , GaN/Mg(OH) 2 , MoS 2 /CdS, CdS/C 2 N, CdS/ZnSe, BlueP/Mg(OH) 2 , BiNbO 4 /ZnWO 4 , C 60 /g‐C 3 N 4 , SiC/MoS 2 , and GaN/BlueP, exhibit enhanced photocatalytic performance. Especially, some ZnO monolayer‐based heterostructures are ZnO/MoS 2 , ZnO/WS 2 , ZnO/WSe 2 , ZnO/AlN, and N‐ZnO/g‐C 3 N 4 .…”

Experimental Investigation with DFT Analysis Towards a Promising Recyclable Photocatalyst from g‐C3N4/ZnS Nanocomposite

“…Also, as shown in Figure 6(c), the potential drop (ΔV) at the g-C 3 N 4 /ZnS interface is 6.8 eV, resulting in an obvious built-in electrostatic potential from the g-C 3 N 4 layer to the ZnS layer and hence the charges (electrons) will be transferred from ZnS to g-C 3 N 4 layer. [39,40] The formation of the built-in electric field across the interface will separate out the photoinduced charge carriers and enhances their migration, thereby prohibiting their recombination possibility. Moreover, this potential is also beneficial for reducing the diffusion of charges between the g-C 3 N 4 sheet and ZnS monolayer.…”

“…As can be seen from the Figure 8(b) that ZnS layer is depleted of charges and hence electronic charge transfer has taken place from ZnS to g-C 3 N 4 layer. [39,40] The charge change in the atoms can further be estimated by Bader charge analysis. [40,41] A quantitative result about the charge change of each atom in g-C 3 N 4 /ZnSheterostructure is shown in Figure 8(c).…”

“…[39,40] The charge change in the atoms can further be estimated by Bader charge analysis. [40,41] A quantitative result about the charge change of each atom in g-C 3 N 4 /ZnSheterostructure is shown in Figure 8(c). It is seen that mainly the Natoms (N 1 -N 4 ) in g-C 3 N 4 layer are liable to gain electrons while Zn 3 , S 1 , and S 3 atoms in ZnS layer are susceptible to lose more electrons.…”

Strain-Tunable Electronic Properties and Band Alignments in GaTe/C2N Heterostructure: a First-Principles Calculation

“…The GaTe/SnI heterostructure was verified to be a large-gap quantum spin Hall insulator and exhibits a noticeable Rashba splitting that can be modulated by changing the interlayer distance of heterosheets [ 30 ]. In addition, construction of semiconductor/C 2 N heterostructures, such as g-C 3 N 4 /C 2 N [ 31 ], MoS 2 /C 2 N [ 32 ], and CdS/C 2 N [ 33 ], demonstrated an enormous potential for promoting the photocatalytic performance of C 2 N due to the efficient separation of the electron-hole pairs, thereby restraining the recombination of photogenerated carriers.…”