Modulating the electronic structure of a hydrogen-bonded organic framework to improve the uranium removal by enhancing hydrogen evolution reaction

Photocatalytic extraction of uranium from solution is one of the most promising technologies for uranium recovery. However, the presence of axial bonds between the two oxygen atoms in UO22+ creates a high activation barrier for electron transfer, which hinders the reduction of UO22+, making it more challenging to reduce U(VI) to U(IV) with conventional photocatalysis. Herein, an ingenious strategy for efficient removal uranium from aqueous solutions by utilizing the photocatalytic hydrogen evolution reaction (HER) process was proposed. In this process, a novelty and high stability bimetallic Co9Ni1-HOF was employed as a high HER performance photocatalyst, with an overpotential of 355 mV at 10 mA cm−2. Benefiting from the excellent HER activity of Co9Ni1-HOF, efficient uranium removal efficiency of ~95.6% within 60 min illumination is achieved. The superior uranium removal performance can be ascribed to the enhanced HER performance due to the incorporation of Ni, and the high affinity between U and OH* resulting from the electron transfer between U and O and N, which can be confirmed by a series of experiments and density functional theory calculation. This work provides a new vision for the efficient removal of uranium by using photocatalytic HER performance.