The synthesis of NH4Zr2F9 and its conversion to ZrO2

Rosette-like ammonium flurorzirconate (NH4Zr2F9) aggregates have been synthesized via a novel reaction route by using zirconium oxychloride, urea, 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4) and hydrochloric acid in ethanol solution. The as-synthesized NH4Zr2F9 can be changed from rosette-like aggregates to hexagonal plates by varying synthesis conditions. Upon calcination at high temperature NH4Zr2F9 transforms from relative dense structure into highly porous ZrO2 with similar morphology consisting of interconnected nanocrystallites.