Harnessing the photocatalytic potential of Janus TlXI (X = S, Se) monolayers for hydrogen and oxygen evolution in solar-driven water splitting

Identifying highly effective and eco-friendly photocatalysts for water splitting is crucial for the sustainable utilization of abundant solar energy. Despite significant advancements, this remains a major challenge. In this study, we explore TlSI and TlSeI Janus monolayers as potential photocatalysts for water splitting, addressing the growing demand for environmentally friendly energy solutions. Using density functional theory (DFT), we investigated the structural and electronic properties of TlXI (X = S, Se) materials. The results indicate that TlXI monolayers exhibit semiconductor behavior, positioning them as promising candidates for photocatalytic applications. Our optical absorption analysis further shows strong absorption in the visible region, suggesting their suitability for solar-driven processes. Additionally, we examined the band edge alignment, which facilitates efficient water redox reactions, further supporting their potential for use in photocatalytic water splitting. Following the examination of stability, electronic band structure, optical absorption, and band edge alignment, our study extends to investigating the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) mechanisms, both of which are critical for water splitting applications. Notably, the TlSeI monolayer exhibits a favorable overpotential of 0.80 V for the OER, which is considered excellent given the inherent complexity of this mechanism. A novel TlXI (X = S, Se) Janus monolayer has been synthesized through an in-silico study. Its structural stability and electronic properties have been investigated. Moreover, its optical absorption has been evaluated, demonstrating its potential as an excellent candidate for photocatalytic applications. Additionally, since water splitting is a viable method for hydrogen production, we have also examined the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). • TlSI and TlSeI Janus monolayers proposed as photocatalysts for water splitting. • First study of electronic and optical properties of TlSI and TlSeI monolayers. • Favorable band edge alignment supports solar-driven redox reactions. • Strong visible-light absorption and high structural stability observed. • Combined properties indicate promise for hydrogen generation applications.