GaS_0.5Te_0.5 monolayer as an efficient water splitting photocatalyst

Abstract

Herein, two-dimensional materials for photocatalytic water splitting are drawing more attention due to the larger surface areas for photocatalytic reactions and shorter migration distances for photogenerated carriers. In this present study, we systematically investigated the fundamental electronic properties of GaSTe monolayers (x = 0, 0.125, 0.25, 0.5, 0.75, 0.875, and 1) for water splitting based on density functional theory (DFT) using the HSE06 functional. The simulation of the defect formation energy under each experimental synthetic condition shows that the Te substitutional impurity in GaS can be relatively easily realized under Ga-rich conditions. Our results show that the GaSTe monolayer is a direct band gap (2.09 eV) semiconductor, which is attributed to the elevation of Te p/p states at the Γ point by the strain effect. Moreover, the GaSTe monolayer has appropriate band edge alignment with respect to the water redox potentials in both acidic and neutral environments. Additionally, the carrier effective mass of the GaSTe monolayer along the direction of Γ → K is smaller than those of pristine GaS and GaTe monolayers, which can cause the carriers to quickly transfer from the photogenerated center to the surface of the photocatalyst. These results imply that the GaSTe monolayer is a promising candidate as a visible-light water splitting photocatalyst, which should be properly synthesized and tested in further experimental investigations.

Band gap engineering of SnS2 nanosheets by anion–anion codoping for visible-light photocatalysis

“…Therefore, the use of 2D materials as photocatalysts has drawn tremendous research interest in both experiments and theoretical calculations for the design of high efficiency water redox photocatalysts. [18][19][20][21][22] Among them, SnS 2 with 2D structures including nanosheets, nanoparticles, and nanoplate, has been successfully synthesized in recent years. [23][24][25] For example, Sun et al 24 have prepared monolayer SnS 2 with three atom thickness and reported that the visible light conversion efficiency can approach 38.7%, which is much higher than that of bulk SnS 2 .…”

Layer-Dependent Electronic Structure of Atomically Resolved Two-Dimensional Gallium Selenide Telluride

“…Among different compositions of M III X VI layered alloys, GaSe 0.5 Te 0.5 and GaS 0.5 Te 0.5 have intriguing potential for diverse applications, from photodetectors 20 to watersplitting catalysts. 21 Although alloying can provide additional tunability of material properties, possible phase segregation in alloys due to immiscibility of constituent elements can hinder optimization. Determining the precise atomic arrangement of multispecies alloys is therefore of critical importance.…”

“…It was found that the monoclinic structure is the stable structure when x ≤ 0.28, while the hexagonal structure is the stable phase when x ≥ 0.32, and for x = 0.28–0.32 both phases coexist. Among different compositions of M III X VI layered alloys, GaSe 0.5 Te 0.5 and GaS 0.5 Te 0.5 have intriguing potential for diverse applications, from photodetectors to water-splitting catalysts …”

Exceptionally tunable electronic, optical and transport properties of two dimensional GaS doped with group II and group IVa elements

“…al. 14 15 have shown the indirect to direct band gap tunability of group-III mono-chalcogenides by means of hetero-structuring and predicted Van Hove singularity near valence band edges.…”

“…al. 14 have theoretically illustrated that Tellurium doped GaS monolayers are best suited for the photocatalytic water splitting. H. R. Jappor et.…”