fig7

Figure 7. (A) Different structures of COF-1 to COF-4 to modulate the excited state electronic structure and charge transport properties for tuning the photocatalytic activities for uranium extraction^[124], Copyright 2023, Springer Nature; (B) Illustration of the energy levels summarizing the main processes involved in charge transfer^[125], Copyright 2024, Wiley-VCH; (C) Preferential growth of N₃-COF along the 001 direction and (D) SEM and TEM (inset) images of N₃-COF and N₃-COF_x^[127], Copyright 2024, American Chemical Society; (E) Recent performance of photocatalysts used for uranium extraction from seawater. Blue: Total uranium uptake capacity; Orange: everyday uranium uptake capacity. COFs: Covalent organic frameworks; TEM: transmission electron microscopy; SEM: scanning electron microscopy.