A general approach to monodisperse perovskite microspheres

•A novel combined hydrothermal and annealing approach has been proposed.•BaTiO3, PbTiO3, SrTiO3, and Pb(Zr,Ti)O3 microspheres were successfully prepared.•The diameter of the microspheres could be well controlled.•The 200 nm Pb(Zr,Ti)O3 microspheres exhibited single crystal features.•The microspheres were very stable after higher temperature calcination.

BaTiO3, PbTiO3, SrTiO3, and Pb(Zr,Ti)O3 microspheres with uniform size and narrow size distribution have been successfully synthesized by a novel hydrothermal and annealing approach. In this approach, the chemical reaction and crystallization process of the ABO3 perovskite oxides were separated in two steps. Spherical particles containing the B-site ions were obtained first via a controlled hydrolysis and aging process. Then, during hydrothermal treatment, the A-site ions were incorporated in situ into the microspheres to form amorphous perovskite microspheres. The particles were further crystallized with preserved spherical morphology under subsequent annealing treatment. The BET surface areas of the TiO2 gel particles, the amorphous PbTiO3 and the as-annealed PbTiO3 microspheres were 245.7 m2/g, 41.67 m2/g and 4.53 m2/g, respectively, showing a significant change of the surface feature in the preparation process. This approach also allowed the microspheres diameters to be manipulated from 100 nm to 1500 nm in a controlled manner. Most of the microspheres were composed by closely packed nano-sized particles. Furthermore, the Pb(Zr,Ti)O3 microspheres with an average diameter of 200 nm exhibited single crystal features, indicating highly oriented growth in the crystallization process. The microspheres were very stable, and still maintained spherical shape after higher temperature calcination.

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