Mechanism of the formation, growth and transformation of BaTi2O5 nanorods synthesized by one-step in molten-salts

In this work, the high-yield synthesis of BaTi 2 O 5 (BT2) nanorods with a growth direction at [020] was achieved in the medium of KCl salt through the molten-salt synthesis (MSS) with Ba(NO 3 ) 2 and anatase TiO 2 as reactants. By optimizing the involved reaction factors including particle sizes, thermal holding durations and crystalline forms of TiO 2 , ultra-pure BT2 nanorods with uniform size were obtained after 45 min of heating at 950 °C. Meanwhile, anatase and rutile TiO 2 were respectively mixed and calcined in KCl to study the formation and transformation process of BT2 nanorods in detail. It was found that anatase TiO 2 tends to merge together and convert into rutile TiO 2 . In particular, the formed rutile TiO 2 reacts with BaO and BaTiO 3 to spontaneously form BT2 nanorods without any presence of rod-like templates. Besides, BT2 takes priority over K 2 Ti 6 O 13 to generate the corresponding nanorods in the molten salt with high content of K + . In addition, the O 2 in air also promotes the formation of nanorods. According to the experimental results, a probable mechanism for the initial formation, subsequent growth and transformation of BT2 nanorods was thus proposed, which helps to facilitate the preparation of BT2-based one-dimensional nanomaterials.