MoS$_2$ and Janus (MoSSe) Based 2D van der Waals heterostructures: Emerging Direct Z-scheme Photocatalysts

TL;DR

This study explores the potential of MoS2 and Janus MoSSe based 2D heterostructures as efficient Z-scheme photocatalysts, revealing promising optical and electronic properties for visible light-driven applications.

Contribution

It introduces a comprehensive first-principles analysis of various MoS2 and MoSSe heterostructures, identifying new promising Z-scheme photocatalysts with enhanced optical and electronic features.

Findings

Type II band alignment in heterostructures enhances photocatalytic efficiency.

Certain heterostructures show strong visible light optical response.

Identified specific heterostructures as most efficient Z-scheme photocatalysts.

Abstract

Two-dimensional (2D) materials viz. transition metal dichalcogenides (TMD) and transition metal oxides (TMO) offer a platform that allows creation of heterostructures with a variety of properties. The optoelectronic industry has observed an upheaval in the research arena of MoS$_2$ based van der Waals (vdW) heterostructures (HTSs) and Janus structures. Therefore, interest towards these structures are backed by the selectivity in terms of electronic and optical properties. The present study investigates the photocatalytic ability of bilayer, MoS$_2$ and Janus (MoSSe) based vdW HTSs viz. MoS$_2$/TMO, MoS$_2$/TMD, MoSSe/TMO and MoSSe/TMD, by first-principles based approach under the framework of (hybrid) density functional theory (DFT) and manybody perturbation theory (GW approximation). We have considered HfS$_2$, ZrS$_2$, TiS$_2$, WS$_2$ and HfO$_2$, T-SnO$_2$, T-PtO$_2$ from the family of TMD and TMO, respectively. The photocatalytic properties of these vdW HTSs are thoroughly investigated and compared with the respective individual monolayers by visualizing their band edge alignment, electron-hole recombination rate and optical properties. Strikingly we observe that, despite most of the individual monolayers do not perform optimally as a photocatalyst, type II band edge alignment is noticed to vdW HTSs and they appear to be efficient for photocatalysis via Z-scheme. Moreover, these HTSs have also shown promising optical response in the visible region. Finally on computing electron-hole recombination rate we find MoSSe/HfS$_2$, MoSSe/TiS$_2$, MoS$_2$/T-SnO$_2$, MoS$_2$/ZrS$_2$ and MoSSe/ZrS$_2$ are probable, most efficient Z-scheme photocatalysts.