Facile green synthesis of a dahlia-like anatase/TiO₂(B) phase junction for boosting the photocatalytic degradation of persistent tetracycline

The simultaneous construction of a phase junction and hierarchical porous architecture can efficiently promote the separation and transfer of photogenerated carriers and then greatly improve the photocatalytic activity of nano-TiO2, while its facile and green preparation is still urgently needed. Herein, a novel dahlia-like TiO2 possessing both an anatase/TiO2(B) phase junction and high specific surface area of 342.7 m(2) g(-1) was successfully fabricated by a facile and green deep eutectic solvent-tuning strategy. The higher specific surface area results from its 3D hierarchical structure assembled by 2D ultrathin nanosheets with mesopores. Owing to the its structural features, the synthesized TiO2 showed a superior photocatalytic activity and favorable stability for persistent tetracycline degradation, compared with pure anatase TiO2, pure TiO2(B) and commercial P25. Based on the trapping experiments of active radical species, ESR spectra and experimental results, a reasonable photocatalytic mechanism of tetracycline degradation was proposed. These research results will provide an efficient strategy for the green preparation and practical application of multifunctional advanced catalysts.