Synthesis of γ-Al2O3 nanoparticles by chemical precipitation method

Highly pure active gamma-Al2O3 nanoparticles were synthesized from aluminum nitrate and ammonium carbonate with a little surfactant by chemical precipitation method. The factors affecting the synthesis process were studied. The properties of gamma-Al2O3 nanoparticles were characterized by DTA, XRD, BET, TEM, laser granularity analysis and impurity content analysis. The results show that the amorphous precursor AI(OH)3 sols are produced by using 0.1 mol/L Al(NO3)(3) (.) 9 H2O and 0.16 mol/L (NH4)(2)CO3 (.) H2O reaction solutions, according to the volume ratio 1.33, adding 0.024% (volume fraction) surfactant PEG600, and reacting at 40 degrees C, 1 000 r/min stirring rate for 15 min. Then, after stabilizing for 24 h, the precursors were extracted and filtrated by vacuum, washed thoroughly with deionized water and dehydrated ethanol, dried in vacuum at 80 degrees C for 8 h, final calcined at 800 degrees C for I h in the air, and high purity active gamma-Al2O3 nanoparticles can be prepared with cubic in crystal system, O-H(7)-FD3M in space group, about 9 nm in crystal grain size, about 20 inn. in particle size and uniform size distribution, 131.35 m(2)/g in BET specific surface area, 7 - 11 nm in pore diameter, and not lower than 99.93% in purity.