| Popis: |
Gallium phosphates were prepared by hydrothermal synthesis under autogeneous pressure. Gel compositions with formulas Ga 2 O 3 .x P 2 O 5 .y HF.z Py(Pr 3 N).70 H 2 O with x=0.5 till 1; y=1 till 5, z=1.7 till 3.4 for Py and 1.5 till 3 for Pr 3 N were obtained under vigorous stirring by successive dissolution in a phosphoric acid/water solution of Ga 2 O 3 , hydrofluoric acid and template. These materials were characterized by XRD, N 2 adsorption-desorption isotherms at 77 K, TG-DTA, FTIR, NH 3 -DRIFT, XPS, SEM, MAS-NMR. The increase of the F/Ga gel composition ratios was found to enhance the crystallinity of the samples and, in certain limits, to improve the thermal stability. |
