Surfactant‐Free and Microporous AlOOH/Al₂O₃ Nanosheets on TiO₂‐Based Nanofibers: A Sustained‐Release Dominated Topotactic Transformation

Abstract Up to now, the synthesis of non‐ligand‐capped 2D transition‐metal nanostructures remained big synthetic challenges. Herein, ultrathin and microporous AlOOH/Al₂O₃ nanosheets were topologically grown on the surface of TiO₂‐based nanofibers by a water‐only hydrothermal strategy starting from electrospun Al₂O₃/TiO₂ nanofibers. The TiO₂ nanofibers lowered the surface energy for the sustained‐released aluminum species and thereby allowed them in situ hydrated to laminar AlOOH. The metastable AlOOH tended to dehydrate to Al₂O₃ simultaneously, leaving a well‐maintained 2D structure with sharp corners and steps, as well as enriched micropores. The nanosheets‐on‐nanofibers exhibited 2856–3370 mg/g of adsorption capacity toward RhB and an efficient removal efficiency over 70% at high throughput (30 mL/h). The promoted light‐harvesting by the perpendicularly attached nanosheets further endowed a significant photodegradation for RhB within 1 h. The presented green and facile approach toward the fabrication of 2D metal oxide nanostructures paves the way to a new variety of oxide nanomaterials.