Fe-MMT/WO₃ composites for chemical and photocatalysis synergistic reduction of uranium (VI).

The preparation of Fe-MMT/WO₃ composites by the hydrothermal method has been explored in this study for the construction of a chemical and photocatalytic catalyst for the reduction of U (VI). This research found that the visible light absorption and reduction potential of the Fe-MMT/WO₃ composites were relatively superior compared to Fe-MMT and WO₃ alone. Based on an evaluation of the performance of the Fe-MMT/WO₃ composites under visible light irradiation, it was discovered that they had greater uranium extraction capacity, where the maximum extraction capacity of U (VI) was determined to be 1862.69 mg g⁻¹, with removal efficiency reaching 93.32%. To investigate the electron transfer and U (VI) to U (IV) reduction mechanisms after the composite, XPS and DFT calculations were conducted. Results showed that Fe (II) is converted to a higher state Fe (III) and WO₃ produce photoelectrons which together reduce U (VI) to U (IV). Moreover, the photoelectrons partially transferred to Fe-MMT with low reduction potential to reduce Fe (III) to Fe (II), allowing iron cycling during uranium extraction to be achieved.