Theoretical Study on Binary Monolayers P3S‐I for Photocatalytic Overall Water Splitting

The utilization of visible light to split water into H₂ and O₂ offers a promising solution to address the escalating global energy crisis and environmental pollution. Compared to conventional three‐dimensional (3D) photocatalysts, anisotropic two‐dimensional (2D) materials exhibit enhanced photocatalytic activity due to their ultrahigh surface area, reduced charge migration distance, and improved efficiency. In this study, we employ a swarm‐intelligence search combined with density functional theory (DFT) calculations to propose a novel series of stable 2D phosphorus sulfides, PₓSᵧ (x, y = 1–6), as promising candidates for photocatalytic water splitting. The P3S‐I monolayer exhibits an optimal bandgap (2.485 eV), appropriate band edge positions (−3.52 eV for CBM and −6.00 eV for VBM at the HSE06 level), high carrier mobility (3246.85 cm² V⁻¹ s⁻¹ for μₑ along the y‐direction and 1039.80 cm² V⁻¹ s⁻¹ for μₕ along the x‐direction), and strong optical absorption coefficients (exceeding 1 × 10⁵ cm⁻¹ within the visible spectrum). Notably, the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are facilitated concurrently at the P and S sites, respectively, driven exclusively by photogenerated electrons and holes.