Photoelectrons storage behavior in SrAl2O4:Eu2+/Dy3+@g-C3N4 persistent photocatalyst for round-the-clock hydrogen generation

Abstract

Solar-driven water splitting for hydrogen production is a pivotal technique for sustainable energy conversion. However, its efficiency is constrained by intermittent solar irradiation and rapid charge recombination. To overcome these limitations, designing a round-the-clock photocatalyst with high charge storage capacity that can still operate effectively under low light flux after sunset and promote charge carrier separation is a promising strategy. Herein, by selecting SrAl₂O₄:Eu²⁺/Dy³⁺ persistent phosphors as electron-trapped centers and g-C₃N₄ semiconductor as visible-light photocatalyst, SrAl₂O₄:Eu²⁺/Dy³⁺@g-C₃N₄ composite has been successfully synthesized via in-situ growth strategy to form a conventional type II heterojunction photocatalyst. Benefiting from the excellent ability of charge storage and release from electron traps and the improved electron-hole separation efficiency, the designed round-the-clock photocatalyst exhibits the improved hydrogen production from 153.8 μmol g⁻¹ h⁻¹ to 560 μmol g⁻¹ h⁻¹ under visible-light irradiation, infrared-light-driven H₂ production of 932 μmol g⁻¹ for 3 h and a dark activity of 269.1 μmol g⁻¹ h⁻¹ lasing for 0.5 h. This work provides a promising strategy for designing a highly efficient photocatalyst for wide-spectral-responsive and all-weather photocatalytic hydrogen production.