Ternary chalcogenides XGaS₂ (X = Ag or Cu) for photocatalytic hydrogen generation from water splitting under irradiation of visible light

Abstract

Ternary chalcogenide silver gallium sulfide (AgGaS2), which has an orthorhombic structure, was already synthesized. However, the feasibility of using the crystal for hydrogen production through photocatalytic water splitting has not been explored. Here, we systematically investigated the structural, electronic, optical, and transport properties of XGaS2 (X = Ag or Cu) with orthorhombic structure by using the first principles calculations. The band alignments indicate that all calculated absolute potentials of the valence and conduction band edges met the requirement of photocatalytic water splitting reaction. The presence of 2.64 and 2.56 eV direct band energy gaps and obvious optical absorption within the visible light range imply that XGaS2 can correspond to solar light. Moreover, the large electron mobility and the obvious differences between electron mobility and hole mobility were identified in XGaS2 structures, which is beneficial to the photocatalytic performance of the water splitting reaction. The present findings can provide a helpful reference for developing novel photocatalytic materials with XGaS2 for hydrogen generation from water splitting under irradiation of visible light.

Colloidal synthesis of AgGa(S1−xSex)2solid solution nanocrystals with composition-dependent crystal phase for efficient photocatalytic degradation of methyl violet

“…Recently, Liu et al have calculated the carrier mobility of orthorhombic and tetragonal XGaS 2 ( X = Ag, Cu) based on the deformation potential (DP) theory proposed by Bardeen and Shockley. 36 The results show that the tetragonal phase presents higher electron and hole mobility than the orthorhombic phase. In addition, Park et al have observed the chalcopyrite (tetragonal) AgInS 2 revealing longer lifetimes than the orthorhombic phase, which can be associated with the enhanced charge transfer.…”

Boosting Photocatalytic Activity Using Carbon Nitride Based 2D/2D van der Waals Heterojunctions

“…TMDCs of groups IV–VI in 0D, 1D, 2D, and 3D morphology such as MoS 2 , WS 2 , TiS 2 , MoSe 2 , and WSe 2 have been extensively explored due to their excellent optical, electronic, and catalytic activities (unusual catalytic activity at the edges), crystalline structure, layer dependent metal to insulator transition, etc. Cadmium sulfide (CdS), the most investigated chalcogenide with a low band gap (∼2.42 eV) and excellent electronic mobility, suffers from the drawback of extreme photocorrosion. − To stabilize and modify the optical properties, a solid solution and homojunction of CdS with ZnS with a fractional composition (Cd (1– x ) Zn x S) have been reported. , Ternary and multinary chalcogenides such as I-III-VI 2 , I 2 -II-IV-VI 4 , Cu 2 MoS 4 , Cu 2 MoSe 4 , Cu 2 WS 4 , AgGaS 2 , LiAlS 2 , LiGaSe 2 , Cu 2 FeSnS 4 , Cu 2 NiSnS 4 , Cu 2 ZnSnS 4 , and Dy 4 S 4 Te 3 prevail upon binary TMDCs because of their tunability, choice of several atomic combinations, suitable band gap, and easy fabrication via solution processing/hydrothermal/solid-state synthesis in the 2D structures. − …”

Dual Polarization Strategy for Boosting Electron–Hole Separation toward Overall Water Splitting within Ferroelectric β-AIBIIIO2 (BIII = P3+, As3+, Sb3+, and Bi3+ for Lone Pairs)

“…This underlines the notion that the local polarization in the xy -plane also plays an important role in charge carrier migration. Previous studies on compounds belonging to the same space group ( Pna 2 1 ), such as AgGaS 2 and CuGaS 2 , have reported electron mobilities as high as 271.2 and 355.3 cm 2 s –1 V –1 , respectively, with hole mobility only reaching an order of magnitude of 10 2 cm 2 s –1 V –1 . For the template β-CuGaO 2 , despite bulk polarization exceeding 80 μC/cm 2 in the z -direction, research has confirmed that μ h and μ e along [001] are only 1691.45 and 147,851.6 cm 2 s –1 V –1 , respectively .…”