Preparation and characterization of different phases of aluminum trifluoride

Several phases (α, e2, and γ) of aluminum fluoride were prepared from precursors such as NH4AlF4, (NH4)3AlF6, and β-AlF3·3H2O using various synthetic strategies. The precursors and the aluminum fluoride phases obtained were characterized by X-ray diffraction (XRD), X-ray fluorescence, scanning electron microscopy (SEM), and infrared spectra (FT-IR). The structural evolution of the precursors to the different phases of aluminum fluoride during thermal treatment was studied by dynamic XRD experiments, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). α- and γ-AlF3 phases were obtained with high BET surface areas (>120 and 30 m2/g, respectively). These aluminum fluorides with high BET areas are of potential interest as supports or catalysts in hydrodechlorination and fluorination reactions.