Strain Induced Enhanced Photocatalytic Activities in Layered Two Dimensional C2N/MoS2 Heterostructure: A Meta-GGA Study

TL;DR

This study investigates how uniaxial, biaxial, and vertical strains affect the electronic properties of C2N/MoS2 heterostructures, revealing strain conditions that optimize photocatalytic water splitting efficiency using first-principles calculations.

Contribution

It demonstrates the impact of different strains on band alignment and water splitting potential in C2N/MoS2 heterostructures, highlighting the effectiveness of the SCAN functional for such studies.

Findings

Vertical strain allows water redox potentials within band edges.

Large compressive strain enables photocatalytic activity.

SCAN functional provides results comparable to hybrid HSE calculations.

Abstract

The improved photocatalytic water splitting using 2D materials has technological importance for economically viable renewable energy. The present study focuses on the effect of uniaxial, biaxial, and vertical strain on the energy gap and band edge positions of C2N/MoS2 van der Waals heterostructures through first-principles density functional theory using PBE and SCAN functionals. The calculations establish that SCAN functional provides comparatively much better results as compared to the PBE for the band gap and band alignment study. The heterostructure exhibits a type- II band alignment which is beneficial for the efficient separation of charge carriers. For a good photocatalyst, the band edge positions should straddle the water redox potentials. It is observed that for both compressive and tensile vertical strain, the water redox potential values lie within the valence band maximum (VBM) and conduction band minimum (CBM) of the heterostructure. On the other hand, for uniaxial and biaxial strain, the system can be used as a useful photocatalyst only for larger compressive strain, whereas for tensile strain, the energy gap between VBM and CBM keeps on decreasing and lie within the water oxidation/reduction potential. Our study also establishes that the meta-GGA SCAN functional shows similar results as compared to the computationally expensive hybrid HSE functionals. The present work can be extremely useful for experimentalists to design artificial heterostructure devices for better performance in photocatalytic water splitting.