Regulation of the Ba/Sr Ratio of (Ba,Sr)TiO₃ and Nanorod Build‐Up through a Topochemical Synthesis Method Using BaTi₂O₅ as the Template

Abstract

One‐dimensional (1D) nano‐ferroelectrics have important applications in the electronics industry, and their high‐quality synthesis has attracted a great deal of interest in the field of the chemistry of materials. In this work, single‐crystal perovskite (Ba 0.5 ,Sr 0.5 )TiO 3 nanorods have been prepared by a topochemical molten‐salt synthesis (TMSS) method. The conversion process and the topochemical mechanism have been investigated, on the basis of XRD, SEM, and TEM analyses. The TMSS method contains two main steps. In the first step, 1D BaTi 2 O 5 nanocrystals are synthesized in a molten environment. In the second step, using these BaTi 2 O 5 monoclinic nanorods as templates, (Ba 0.5 ,Sr 0.5 )TiO 3 perovskite nanorods are constructed through a topochemical reaction. The results reveal that the 1D morphology of (Ba 0.5 ,Sr 0.5 )TiO 3 can be maintained over a wide temperature range, between 800 °C and 1000 °C. Using the 1D BaTi 2 O 5 as a template, the 1D morphology of (Ba x ,Sr 1– x )TiO 3 ( x = 0.5–1) can be obtained at 900 °C, and the 1D morphology is almost independent of the Ba/Sr ratio. In addition, changing the combination of the A‐site complex ions significantly affects the morphology of the product. For (Ba,Ca)TiO 3 , the product is assembled in a 1D direction by nanoparticles, not regular nanorods. This TMSS method is facile and can be developed to construct other orientated functional materials.