Effect of NaOH concentration on formation of Ba4Ti13O30 and BaTi5O11 nanocrystals prepared by hydrothermal method

Abstract

• The rice-like BaTi 5 O 11 nanocrystals were formed at NaOH concentration of 1 M. • The Ba 4 Ti 13 O 30 nanowires were prepared at NaOH concentration of 3 M. • The phase evolution from BaTi 5 O 11 to Ba 4 Ti 13 O 30 was controlled by NaOH content. The Ba 4 Ti 13 O 30 and BaTi 5 O 11 nanocrystals were synthesized by a hydrothermal method, and the effect of NaOH concentration on formation of Ba 4 Ti 13 O 30 and BaTi 5 O 11 nanocrystals was investigated. In the Ba-Ti precursors, the concentrations of Ba 2+ and Ti 4+ ions were kept at 0.018 and 0.082 mol/L, and the NaOH concentration changed from 1 to 8 mol/L. As the Ba-Ti precursors were heated in the autoclave at 280 °C for 20 h with vigorous stirring, the pure BaTi 5 O 11 nanocrystals with rice-like morphology were obtained at NaOH concentration of 1 mol/L, and the Ba 4 Ti 13 O 30 nanowires were co-formed with the rice-like BaTi 5 O 11 nanocrystals at NaOH concentration of 2 mol/L. With increasing the NaOH concentration, the amount of Ba 4 Ti 13 O 30 nanowires increased. The phase evolution from monoclinic BaTi 5 O 11 to orthorhombic Ba 4 Ti 13 O 30 could be controlled by adjusting NaOH concentration.