Fabrication of Porous ZrO2 Nanostructures with Controlled Crystalline Phases and Structures via a Facile and Cost-Effective Hydrothermal Approach

In the present work, porous zirconia nanostructures with different crystalline phases and structures were fabricated at low temperatures via a facile, green, and cost-effective two-step solution-phase strategy involving remarkably rapid nucleation and following a kinetically controlled hydrothermal process. ZrO2 nanostructures with different crystalline phases and structures were achieved simply by varying the concentration of the added sodium borohydride precipitant without the use of any additional surfactants and templates, and the specific surface area of ZrO2 could reach as high as 275 m2 g–1. In the synthesis process, the decomposition of NaBH4 could drive the dynamical perturbation for the reaction system through the bubble effect originating from inosculation and blast of hydrogen in situ generated, which played a crucial role in controlling the formation of ZrO2 nanostructures. Moreover, the present method could be explored for fabricating other fundamentally and technologically important metal oxides (e.g., CeO2, TiO2), indicative of good versatility.