Insights into the OER/ORR/HER activity of a new MXene-family SnSiGeN4 photocatalyst for water splitting: a first-principles study

Abstract

The development of efficient and cost-effective catalysts for clean energy conversion remains a central challenge in materials science. Although platinum- and titanium-based catalysts serve as benchmark systems, their scarcity and high cost hinder large-scale deployment. In this study, we propose a newly predicted SnSiGeN₄ MXene-family monolayer as a promising candidate for the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER). Using first-principles calculations, we investigated its electronic, vibrational, and optical properties across multiple exchange–correlation functionals, including hybrid frameworks, revealing a wide and variable band gap. Simulated infrared and Raman spectra further confirm its dynamical stability and the presence of catalytically active sites. Based on these results, we further studied photocatalytic reaction analysis demonstrates that the computed overpotentials for the OER, ORR, and HER are comparable to those of Pt-based catalysts and even outperform Ir-based systems, positioning SnSiGeN₄ as a sustainable, high-performance platform for next-generation UV-visible-light-driven photocatalysis.