Photocatalysis-assisted transition of uranium from the soluble U(VI) to the insoluble U(IV) is an efficient strategy for eliminating uranium. Herein, a novel 3D structure composite aerogel (3D RGO@TiO₂) was applied to photoreduction of U(VI) under visible light. The introduction of RGO could expand the light absorption region and facilitate efficient charge separation of 3D RGO@TiO₂. Therefore, 3D RGO@TiO₂-3 (where the mass ratio of GO and H-TiO₂ was 1 : 1) achieved the greatest U(VI) reduction rate (0.03752 min⁻¹) that is almost five times higher than that of RGO. Meanwhile, the reaction between photogenerated electrons and superoxide radicals ˙O₂⁻ played the dominant role in reducing U(VI) to (UO₂)O₂·2H₂O in air-equilibrated wastewater. This study not only provides new insights into remediation of the radioactive environment but also proves the application prospect of the 3D RGO@TiO₂ in the photocatalytic field.

中文翻译：

---

由还原氧化石墨烯和中空 TiO2 球体构建的 3D 结构气凝胶，用于空气平衡废水中 U(VI) 的有效可见光驱动光还原

光催化辅助铀从可溶性 U( VI ) 到不溶性 U( IV ) 的转变是消除铀的有效策略。在此，一种新型的 3D 结构复合气凝胶（3D RGO@TiO ₂）应用于可见光下U( VI ) 的光还原。RGO的引入可以扩大光吸收区域并促进3D RGO@TiO _{2 的}有效电荷分离。因此，3D RGO@TiO ₂ -3（其中GO和H-TiO ₂的质量比为1 : 1）实现了最大的U（VI）还原率（0.03752 min ^-1) 几乎是 RGO 的五倍。同时，光生电子与超氧自由基˙O ₂ ^-之间的反应在空气平衡废水中将U( VI )还原为(UO ₂ )O ₂ ·2H ₂ O 中起主导作用。该研究不仅为放射性环境的修复提供了新的见解，而且证明了3D RGO@TiO ₂在光催化领域的应用前景。