Perovskite BaZrO3 hollow micro- and nanospheres: controllable fabrication, photoluminescence and adsorption of reactive dyes

Size tunable perovskite-type BaZrO3 hollow micro- and nanospheres have been hydrothermally synthesized in a strong basic medium without any organic or inorganic templates. The products experienced morphology variations of solid, core-shell and hollow nanospheres by alternatively adjusting the base concentration, the reaction temperature or the reaction duration. Investigations on the synthetic parameters revealed that the formation of BaZrO3 hollow nanospheres was driven by the Ostwald ripening process. BaZrO3 hollow nanospheres were produced when the reaction temperature and the base concentration were in a suitable rate due to their functions to elevate the crystal growth speed and the diffusion rate. XRD patterns disclosed the cubic perovskite structure of BaZrO3 hollow spheres. HRTEM and SAED measurements revealed the single crystal nature of a single BaZrO3 hollow nanosphere. The hollow spheres were size tunable by simply adjusting the base concentration at a suitable temperature, which was rationally elucidated by the sol–gel theory. The hollow nanospheres exhibited an intensive green light emission and excellent reactive dye adsorption.