An imidazole-based covalent-organic framework enabling a super-efficiency in sunlight-driven uranium extraction from seawater

Uranium extraction from seawater represents an effective way to solve the difficulty of the insufficient uranium supply chain. However, this route is still restricted by the low extraction efficiency of reported adsorbents. Here, we find that reversing the donor-acceptor in imidazole-based COFs (covalent-organic frameworks) would be effective for enhancing the extraction efficiency of uranium. As a result, the TI-COF is found to enable a uranium extraction efficiency up to 8.8 mg g-1 day-1 from seawater under visible light irradiation, exceeding all established adsorbents for such use, and an unprecedented uranium extraction efficiency up to 6.9 mg g-1 day-1 from seawater under natural sunlight. The natural sunlight is for the first time used to acquire the key of nuclear energy, uranium, from natural seawater with an ultrahigh extraction efficiency of 6.9 mg g-1 day-1 upon a novel COF photocatalyst with ultralow exciton binding energy.