Effective Charge Separation in a Dual-Single-Atom Photocatalyst for Sacrificial Agent-Free H₂ Evolution

The challenge of achieving efficient photocatalytic H₂ production from water splitting without sacrificial agents remains a significant hurdle. Herein, we demonstrate that the dual doping of Cu/Co single atoms on Li-reduced blue TiO₂ (Cu-Co SA/BTO) can effectively modulate the charge separation of photogenerated carriers during photocatalytic pure water splitting. Remarkably, the H₂ evolution rate of Cu-Co SA/BTO achieves a remarkable value of 1238.15 μmol·g^-1·h^-1, surpassing that of BTO by 11 times. Particularly, femtosecond transient absorption spectroscopy (fs-TA) and differential charge densities reveal that the efficient electron-hole separation originates from the doping of Cu/Co dual-single atoms. The doping of Cu single atoms boosts electron transfer from the TiO₂ conduction band to Cu atoms, while the doping of Co single atoms facilitates photogenerated hole migration to Co single atoms from TiO₂. This work establishes a promising photocatalyst design strategy for achieving highly efficient H₂ evolution through pure water splitting, marking a significant step toward sustainable and green energy production.