Morphological evolution of hierarchical nickel titanates by elevation of the solvothermal temperature

In this study, the morphological evolution of hierarchical nickel titanates was first-ever investigated by simply raising the solvothermal temperature. At room temperature, irregular aggregates of anatase TiO2 nanoparticles were reluctantly formed. Increasing the temperature to 100 degrees C resulted in the assembly of 3D drum-shaped nickel titanate clusters where the three-dimensional geometry was constructed via coalescent nanopartides with a mean size of 126.8 nm. An intermediate stage containing circular cylinders and irregular prisms was obtained at intermediate temperatures. Further elevation of the solvothermal temperature to 160 degrees C and 180 degrees C gave 1D uniform hexagonal nanoprisms of nickel titanates. Increasing the solvothermal temperature accelerates the nucleation rate, which drastically promotes crystallization and self-assembly, thereby evolving to the hierarchical structure of NiTiO3. (C) 2014 Elsevier B.V. All rights reserved.