Cyano-Functionalized Graphitic Carbon Nitride with Adsorption and Photoreduction Isosite Achieving Efficient Uranium Extraction from Seawater

Photocatalytic uranium extraction from seawater is an ideal strategy to obtain uranium resources. Herein, the cyano-functionalized graphitic carbon nitride (g-C3N4-CN) with an isosite structure of adsorption and photoreduction for U(VI) is successfully prepared to achieve efficient photocatalytic uranium extraction from seawater. As the key of the isosite structure, the cyano group not only dramatically promotes the separation of photogenerated charges of g-C3N4-CN and enriched electrons around it, but also greatly improves the adsorption capacity and selectivity for U(VI) over g-C3N4-CN by complexing with U(VI). Therefore, g-C3N4-CN exhibits efficient and stable photocatalytic U(VI) reduction performance, with a saturated uranium extraction capacity of 2644.3 mg g-1, significantly higher than most reported g-C3N4-based photocatalysts. Moreover, it also performs well in solar light-driven uranium extraction from actual seawater. Briefly, this work illustrates the importance of constructing the isosite structure of adsorption and photoreduction for U(VI) in improving the photocatalytic uranium extraction performance. The cyano-functionalized graphitic carbon nitride with an isosite structure of adsorption and photoreduction for U(VI) is successfully prepared, which achieves efficient and stable photocatalytic U(VI) reduction performance, with a saturated uranium extraction capacity of 2644.3 mg g-1, significantly higher than most reported g-C3N4-based photocatalysts. Moreover, it also performs well in solar light-driven uranium extraction from actual seawater.image