Nitrogen‐Deficient Graphitic Carbon Nitride with Selective Adsorption and Photoreduction Isosite for Efficient Uranium Extraction from Seawater Under Air Atmosphere

Abstract Photocatalytic uranium extraction from seawater is an ideal approach to acquiring uranium resources, yet its performance is often compromised by ambient air interference. Herein, the nitrogen‐deficient graphitic carbon nitride (Nv‐g‐C 3 N 4 ) with an isosite structure of selective adsorption and photoreduction for U(VI) is successfully constructed, achieving efficient photocatalytic uranium extraction from seawater under air atmosphere. The study reveals that cyano groups reconstructed through nitrogen defects demonstrate robust electron‐withdrawing capability, significantly promoting the separation of photogenerated charges and driving electron accumulation around these groups. Besides, the nitrogen‐deficient structure endowes Nv‐g‐C 3 N 4 with superior selectivity toward U(VI), evidenced by its markedly lower adsorption energy for U(VI) compared to O 2 . Therefore, even under air atmosphere, Nv‐g‐C 3 N 4 exhibits excellent photocatalytic uranium extraction performance, exceeding cyano‐functionalized g‐C 3 N 4 by 39.7 times. It also achieves a record‐high saturation uranium extraction capacity of 3625.3 mg g −1 , significantly surpassing other reported g‐C 3 N 4 ‐based photocatalysts. Remarkably, under natural sunlight, the Nv‐g‐C 3 N 4 ‐based aerogel achieves a uranium extraction capacity of 43.2 mg g −1 in spiked natural seawater. Briefly, this work illustrates the importance of constructing the defect engineer as an isosite structure of selective adsorption and photoreduction for U(VI) in photocatalytic uranium extraction from seawater.