Synergistic Synthesis of Hierarchical Hollow Mesoporous Metal–Organic Frameworks by One‐Step Strategy for Selective Uranium Capture

Synthesizing Metal–organic frameworks (MOFs) featuring both hollow architectures and mesoporous channels (H‐OM‐MOFs) remains a considerable synthetic challenge, often involving complex multistep procedures. Herein, we report a facile one‐step strategy for the rapid synthesis of such hierarchically structured MOFs. By innovatively introducing 2‐amino terephthalic acid into the OM‐Ce‐MOF reaction system, a crystallinity gradient is established between the core and shell of the forming nanoparticles. This gradient drives a controlled self‐etching of the inner core while maintains its structural integrity on its outer shell, resulting in a well‐defined hollow structure. The dimensions of the internal cavity and the uniform mesoporous channels can be precisely regulated by reaction parameters, with the complete formation of the structure in just 25 min. This exceptional structure maximizes mass transfer efficiency and active sites accessibility. Consequently, the optimized H‐OM‐Ce‐MOF‐NH 2 achieves an extraordinary [UO 2 (CO 3 ) 3 ] 4− uptake capacity of 95.47 mg·g −1 , coupled with ultra‐fast reaction kinetics (over 90% saturation within 20 min), high selectivity, and excellent stability. These findings identify a promising candidate for seawater uranium extraction and, of broader significance, establish a general one‐step strategy for synthesizing hierarchical porous MOFs.