Computational study of two-dimensional SnGe2N4 as a promising photocatalyst for the oxygen evolution reaction

Abstract

In the domain of photocatalysis, the oxygen evolution reaction (OER) serves as a crucial process in sustainable energy production. The development of efficient photocatalysts for the OER is therefore highly desirable. Two-dimensional (2D) materials, with their distinct structural and electronic properties, offer great opportunities for improving oxygen production. We propose H and H′ polymorphs of SnGe₂N₄ as appealing photocatalysts driving the OER using first-principles calculations together with non-adiabatic molecular dynamics (NAMD). The electronic properties and charge carrier dynamics of SnGe₂N₄ were evaluated, revealing insights into its potential for the OER under solar irradiation. Our findings indicate that SnGe₂N₄ has a favorable bandgap (∼2 eV) with appropriate band edges for the OER, promoting charge separation and transport. A significant difference in mobility facilitates electron and hole separation, leading to elevated reaction rates in the material. Moreover, the band edge alignment suggests the incorporation of water oxidation potential favoring the OER. The computed reaction pathways and free energy analysis show that SnGe₂N₄ can function as an effective photo-catalyst for the OER. Non-adiabatic coupling (NAC) matrix elements further ensure the ultrafast carrier dynamics, facilitating efficient charge transfer and slow recombination rates. Our findings highlight 2D SnGe₂N₄ as an appealing candidate for the OER.