Spatially Directed Charge Transfer in Al-Doped SrTiO₃ for Efficient Hydrogen Production From Seawater

Efficient photocatalytic hydrogen production from seawater requires not only active catalytic sites but also spatially directed charge transfer to suppress electron-hole (e^--h⁺) recombination and maintain catalytic stability in complex ionic environments. Herein, a spatially engineered Al-doped SrTiO₃-based photocatalyst was constructed by integrating Rh-Cr-Co cocatalyst sites with carbon quantum dots (CQDs). In this work, Al-doped SrTiO₃ serves as the semiconductor framework for light absorption and charge generation, while the multicomponent cocatalyst promotes interfacial redox reactions and charge separation. The optimized photocatalyst, denoted as CQDs/RhCrCo-ST, exhibits hydrogen production rates of 31.8 mmol g^-1 h^-1 in natural seawater. Moreover, it retains 81% of its initial activity after 42 h of cycling in natural seawater, demonstrating good durability under saline conditions. Structural and spectroscopic analyses suggest that the enhanced performance originates from improved interfacial charge transfer and spatially separated redox processes within the Al-doped SrTiO₃-based photocatalytic system. This work provides an effective way for designing efficient and stable oxide photocatalysts for solar hydrogen production from seawater.