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

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 BaTiO 3 /g-C 3 N 4 (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, BaTiO 3 /g-C 3 N 4 -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 BaTiO 3 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 BaTiO 3 /g-C 3 N 4 heterojunctions offers a promising strategy and a robust experimental basis for the development of high-efficiency photocatalysts of uranium remediation.