Covalent triazine framework nanosheets for photo-enhanced uranium extraction

Uranium extraction is the cornerstone of the sustainable development of the nuclear industry. Although a variety of porous framework materials for uranium extraction have been explored over the past few decades, almost all of them have been limited to bulk powder materials. In particular, due to the strong interlayer π-π interaction, the specific recognition sites and photocatalytic active centers of bulk two-dimensional framework materials are severely buried, resulting in the inability to exploit the optimal performance of the materials. In this study, a novel hydroquinone modified covalent triazine frame nanosheets (H-CTF-NSs) is reported for the first time, which is designed for specific extraction and photocatalytic reduction of uranium. The densely distributed hydroquinone and triazine units in the H-CTF-NSs synergistically form high-affinity binding sites, and the ultrathin nanosheets facilitate the exposure of binding sites and catalytically active centers, and accelerate the diffusion of uranyl ions, it is ideally suited as an advanced platform for the selective extraction and efficient reduction of U(VI). Remarkably, H-CTF-NSs demonstrated an unprecedented uranium extraction capacity of 3230.3 mg/g, which is almost 1.71 times that of its bulk counterpart H-CTF, making it one of the best uranium-trapping photocatalysts known to date.