Synthesis of lamellar niobic acid nanorods via proton-exchange and their conversion to T-Nb₂O₅ nanorods

We report the topochemical synthesis of lamellar niobic acid (H ₂Nb₂O₆) nanorods via proton-exchange from single-crystal CaNb₂O₆ nanorods with layered structure. The obtained H₂Nb₂O₆ nanorods were then converted to T-Nb₂O₅ nanorods with a pseudo-hexagonal structure by thermal treatment in air. The one-dimensional characteristic of the CaNb₂O₆ nanorods remained during their transformation to H₂Nb₂O₆ and then to T-Nb₂O ₅ nanorods. The structure transformation during the formation of T-Nb₂O₅ nanorods was investigated in detail using high-resolution transmission electron microscopy, and the results show that polycrystalline Nb₂O₅ nanorods were formed although the one-dimensional characteristic was well retained. The existence of texturing as well as dislocations in T-Nb₂O₅ nanorods was revealed.