MXene-intercalation induced ordered brick-mortar structures of allomorph junctions for enhanced flexibility in TiO2 nanofibers and photocatalytic efficiency

Continuous TiO 2 nanofibers (NFs) with the merits of high photochemical activity, adjustable active sites, and easy to recycle have triggered a huge interest in the catalysis fields. Nevertheless, they are easy to break due to the intrinsic brittleness of ceramic TiO 2 . Here, we report a Mxene-intercalation toughening strategy to fabricate flexible TiO 2 NF films with a sol–gel electrospinning method followed by a low-temperature calcination. The in-situ doping of MXene (Ti 3 C 2 T x ) nanosheets in TiO 2 NFs reduces the grain sizes and introduces 2D defective MXene-derived TiO 2 planes, the former creates sinuous grain boundaries that can reduce crack propagation, while the latter generates elastic brick–mortar structures of allomorph junctions that can absorb more external work. The dual functions remarkably enhance the breaking strength of TiO 2 NFs from 0.06 to 0.16 MPa. Fascinatingly, this strategy reduces the bandgap of TiO 2 and more efficiently conduct photogenerated carriers. The evolution rate of photocatalytic CO 2 reduction into CH 4 reaches 31.6 μmol/g/h without using sacrificing agents and photosensitizers. The reported facile strategy simultaneously enhances the flexibility of TiO 2 nanofibers and photocatalytic efficiency.