Cobalt Single Atom‐Enhanced Photocatalysis: Hetero‐Phase Elemental Phosphorus for Visible Light Hydrogen Production from Pure Water Splitting

Abstract Elemental P is considered a compelling option for constructing a simple, cost‐effective, and full‐spectrum responsive catalytic system for hydrogen production, while its full potential for overall water‐splitting reactions remains underexplored. This study introduces a novel cobalt single‐atom‐assisted photocatalytic system for efficient hydrogen production via water splitting. Utilizing an in situ surface phase transformation, amorphous red phosphorus (a‐RP) is converted into crystalline black phosphorus (c‐BP), forming a Z‐scheme heterojunction with cobalt single atoms (Co ₁ ) uniformly dispersed across the heterojunction surface. Advanced characterization techniques confirm the intimate contact and strong electronic interactions between Co ₁ , c‐BP, and a‐RP, significantly enhancing photocatalytic performance. This system achieves a high hydrogen production rate of ≈2497 µmol g ⁻¹ h ⁻¹ from pure water splitting under visible light irradiation and a remarkable solar‐to‐hydrogen (STH) efficiency of 0.86%, outperforming most reported photocatalytic systems. This study highlights the potential of single‐atom catalysts in enhancing the performance of photocatalysts. It provides a new perspective on designing efficient and stable elemental‐based photocatalytic systems for sustainable hydrogen production.