The study presents a novel Z-scheme Bi₂O₃/g-C₃N₄ hollow core-shell heterojunction photocatalyst designed for efficient photocatalytic uranium extraction from radioactive nuclear wastewater and seawater. This catalyst demonstrates high extraction efficiency, achieving 98.4% and 99.0% uranium extraction rates under aerobic and oxygen-free conditions, respectively. The exceptional performance is attributed to the unique hollow core-shell structure, which provides a large number of active sites, and the Z-scheme heterojunction, which enhances charge transfer and lifetime. The catalyst maintains its efficiency under various environmental conditions, including pH and inorganic ion influences. The mechanism of uranium extraction is investigated, revealing that H₂O₂ plays a crucial role in forming different final products. The findings provide valuable insights into the fundamental mechanisms of photocatalytic uranium extraction and highlight the potential of this method for practical applications.The study presents a novel Z-scheme Bi₂O₃/g-C₃N₄ hollow core-shell heterojunction photocatalyst designed for efficient photocatalytic uranium extraction from radioactive nuclear wastewater and seawater. This catalyst demonstrates high extraction efficiency, achieving 98.4% and 99.0% uranium extraction rates under aerobic and oxygen-free conditions, respectively. The exceptional performance is attributed to the unique hollow core-shell structure, which provides a large number of active sites, and the Z-scheme heterojunction, which enhances charge transfer and lifetime. The catalyst maintains its efficiency under various environmental conditions, including pH and inorganic ion influences. The mechanism of uranium extraction is investigated, revealing that H₂O₂ plays a crucial role in forming different final products. The findings provide valuable insights into the fundamental mechanisms of photocatalytic uranium extraction and highlight the potential of this method for practical applications.