Photocatalytic removal and mechanistic investigation of U(VI) using BaTiO₃/g-C₃N₄ heterojunctions with enhanced...

With the extensive deployment of nuclear energy, uranium contamination-particularly in the hexavalent form U(VI)-has become an escalating threat to aquatic systems. Photocatalytic reduction has emerged as a green and sustainable strategy for environmental remediation. However, achieving high photocatalytic efficiency and effective solar energy utilization remains a significant challenge. In this study, a series of BaTiO₃/g-C₃N₄ (BTO/CN) type-II heterojunction photocatalysts were synthesized through a simple hydrothermal method with rational band alignment. The effect of different BTO/CN ratios on U(VI) removal efficiency was evaluated. Among the tested compositions, BaTiO₃/g-C₃N₄-4 exhibited the highest photocatalytic performance, achieving a U(VI) removal efficiency of 96.2% within 20 min of visible light irradiation-significantly outperforming both individual components and other composite ratios. The optimized heterojunction effectively modulated the electronic band structure, facilitating the rapid separation of photogenerated electron-hole (e^--h⁺) pairs. Furthermore, the synergistic effect between the heterojunction interface and the intrinsic ferroelectric properties of BaTiO₃ significantly suppressed charge carrier recombination and extended the visible-light absorption range. This, in turn, substantially enhanced the overall photocatalytic efficiency of the system. The rational design of BaTiO₃/g-C₃N₄ heterojunctions offers a promising strategy and a robust experimental basis for the development of high-efficiency photocatalysts of uranium remediation.