Photocatalytic uranium extraction can surpass the intrinsic capacity limits of adsorption by converting soluble uranyl into insoluble uranium peroxides via H2O2 generation. However, this process requires simultaneous local enrichment of H2O2 and UO22+ beyond the solubility product constant, which is difficult to achieve in continuously flowing and ultra-dilute seawater. Here we report a hollow hierarchical covalent organic framework (COF) microcavity reactor, HH-COF-(CN/AO)x, that spatially decouples H2O2 generation from uranyl capture to overcome this thermodynamic barrier via a bidirectional reactant flux coupling strategy. A cyano-functionalized inner layer produces and stores H2O2 in a central cavity, whereas an amidoxime-rich outer layer selectively enriches uranyl ions. The convergence of outward H2O2 flux and inward uranyl adsorption establishes a persistent high-concentration interface that supports continuous formation of insoluble uranium peroxide. The optimized HH-COF-(CN/AO)0.35 achieves 25.1 mg g−1 uranium uptake in natural seawater, 3.9 times that of the non-hollow analog, which demonstrates a generalizable strategy for manipulating reactant fluxes in ultra-dilute environments for realizing effective resource extraction from water environment. ‘Photocatalytic uranium extraction can surpass intrinsic capacity limits of adsorption but is shows limitations in continuously flowing and ultra dilute seawater. Here the authors report a hollow hierarchical covalent organic framework microcavity reactor that decouples H2O2 generation from uranyl capture via bidirectional reactant flux coupling. ’
Zhang et al. (Fri,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: