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 (H2Nb2O6) 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-Nb2O5 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.