Solvothermal synthesis of size-controlled ZrO2 microspheres via hydrolysis of alkoxides modified with acetylacetone

► ZrO2 microspheres were prepared from Zr(OC3H7n)4 solutions with acetylacetone. ► The size of ZrO2 microspheres depends on the hydrolysis rate of Zr(OC3H7n)4. ► Non-aggregated, homogeneous ZrO2 microspheres can be observed even by optical microscopy. ► The crystallinity of the ZrO2 spheres was improved by the heat treatment.