First-principles study on the photocatalytic field of two-dimensional Janus BiSY (Y = I, Br, Cl) monolayers

Abstract

Two-dimensional photocatalytic materials have emerged as prominent materials within ecological and energy catalysis in recent years. Among these materials, two-dimensional Janus structures, including PdXY (X = S, Se; Y = Se, Te), MXY (M = Mo, W; X, Y = S, Se, Te), and MSiGeN₄ (M = Mo, W), have been highlighted as prospective candidates for water-splitting photocatalysts. In this paper, we have explored BiSY (Y = I, Br, Cl) as a promising material for overall water-splitting, utilizing first-principles calculations to investigate the geometric structure, stability, electronic structure, and optical properties. By analyzing the results of phonon band structures, molecular dynamics simulations, and the elasticity coefficient, we can establish the system stability of BiSY (Y = I, Br, Cl). And HSE06 energy band calculations and band edge position calculations demonstrated that BiSY (Y = I, Br, Cl) possesses an appropriate band gap. Moreover, the absorption spectra and step reaction diagrams validated the feasibility of photocatalytic water-splitting of BiSY (Y = I, Br, Cl). Additionally, we confirmed that biaxial strain can change the band edge position of BiSY (Y = I, Br, Cl). Our comprehensive analysis shows that BiSY (Y = I, Br, Cl) is a potential candidate for efficient water-splitting photocatalysts. This study contributes to the growing collection of two-dimensional Janus photocatalysts.