Synergistic enhancement of NC-GCN/Ag2O photocatalytic reduction of uranium by D-A and p-n junction structures

• Published in: Journal of molecular liquids 2024-09, Vol.409, p.125440, Article 125440
• Main Authors: Li, Zhouzhou, Li, Zheng, He, Feng, He, Wen, Chen, Qixu, Wang, Hongqing
• Format: Article
• Language: English
• Subjects: Electron-absorbing groups; p-n heterojunction; Photo-reduction; U(Ⅵ)
• ISSN: 0167-7322
• DOI: 10.1016/j.molliq.2024.125440

[Display omitted] •Synthesis of a new U(VI) catalyst for photocatalytic reduction, NC-GCN10/Ag2O(1:2).•A new strategy to enhance the performance of materials for photocatalytic reduction of U(VI).•Intramolecular D-A structure and p-n heterojunction co-promote the photocatalytic performance of GCN.•The removal efficiency of U(Ⅵ) by NC-GCN10/Ag2O(1:2) photocatalyst was seven times as much as GCN.•A mechanism of photocatalytic reduction of U(VI) was proposed. Recently, how to improve the photocatalytic uranium removal performance of Graphite-phase carbon nitride (GCN) has always been a hot research topic. In this paper, a new strategy based on p-n junction and D-A structure is proposed to improve the photocatalytic performance. And as a result, a novel cyano modified photocatalytic material NC-GCN/Ag2O was designed and prepared for the reduction of U(VI). Interestingly, the material shows better adsorption performance for U(VI) in the dark treatment stage, and its removal of U(VI) is close to 70 % under the initial U(VI) concentration of 20 ppm and the solid–liquid ratio of 0.2 g/L. And the adsorption is in accordance with the Langmuir model and Pseudo second order model. After 30 min of illumination, the removal rate of U(VI) can reach 93.2 %, significantly higher than that of GCN (13.6 %) and NC-GCN10(37.7 %). It’s worth mentioning that photocatalytic reduction dominated the adsorption-reduction process for U(VI) removal after light exposure. In addition, after four cycles, the removal of U(VI) from the composite material decreased by only 5 % with no change in the crystal structure, i.e., it has good reusability and stability. Meanwhile, there was no significant interference with other ions except for Cu2+ and V5+, which had a weak interference. Finally, a new mechanism for U(Ⅵ) reduction was proposed.