2D Ge₂Se₂P₄ Monolayer: A Versatile Photocatalyst for Sustainable Water Splitting

This study aims to identify photo-/electrocatalysts that can enhance the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR), which are of utmost importance in electro-/photochemical energy systems, such as solar energy, fuel cells, water electrolyzers, or metal-air batteries. Our study focused on investigating the 2D Ge2Se2P4 monolayer and found that it exhibits a bifunctional photocatalyst with a very high solar-to-hydrogen efficiency. The two-dimensional (2D) Ge2Se2P4 monolayer has superior HER activity compared to that of most 2D materials, and it also outperforms the reference catalysts IrO2(110) and Pt(111) in terms of low overpotential values for ORR and OER mechanisms. Such superior catalytic performance in the 2D Ge2Se2P4 monolayer can be attributed to its electron states, charge transfer process, and suitable band alignments referring to normal hydrogen electrodes. Overall, the study suggests that the Ge2Se2P4 monolayer could be an excellent bifunctional catalyst for advancing photo-/electrochemical energy systems.