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 (Co₁) uniformly dispersed across the heterojunction surface. Advanced characterization techniques confirm the intimate contact and strong electronic interactions between Co₁, 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.