Controllable preparation of two-dimensional oriented BaTiO3 polycrystals from K0.8Ti1.73Li0.27O4 crystals by a one-step solvothermal process

Abstract

Titanate precursors play an important role in obtaining oriented titanate materials via topochemical conversion. In this study, a two-dimensional (2D) K0.8Ti1.73Li0.27O4 (KTLO) crystal was successfully prepared by a one-step solvothermal process using TiO2, LiOH・H2O, and KOH as raw materials in ethanol/water mixed solvent for the first time. Meanwhile, the conditions and influencing factors for the solvothermal preparation of KTLO were investigated and analysed. With a ratio of ethanol/water of 20:5, better 2D KTLO can be obtained by reacting at 150 ◦C for 24 h. On this basis, KTLO was used directly to perform solvothermal treatment with Ba(OH)2, and 2D BaTiO3 (BT) was easily prepared by adjusting the reaction conditions (concentration, temperature, and time). When the solvothermal treatment was carried out in 0.5 mol/L Ba(OH)2 solution at 80 ◦C for 1.5 h, 2D BT crystals could be easily obtained through the topochemical reaction mechanism. This strategy not only develops new methods for preparing precursors but also greatly simplifies the preparation process of BT and provides new research ideas for the preparation of functional materials.