Synthesis of novel nanostructured γ-Al2O3 by pyrolysis of aluminiumoxyhydride–HAlO

Abstract

Thermolysis of amorphous nanosized aluminiumoxyhydride, HAlO, at 450 °C led to its decomposition into amorphous Al₂O₃, finely divided aluminium metal, and H₂ gas. Thermolysis at 800–1100 °C afforded γ-Al₂O₃ nanorods consisting of aggregated nanocrystallites. The size of the nanorods varied between diameters of 30–300 nm and lengths of up to several µm leading to aspect ratios of 3–30. The onset of crystallization was at approximately 800 °C. Yields of up to 40% were obtained by thermolysis at 1100 °C for 6 h. Lower temperatures resulted in lower nanorod yield. The presence of aluminium metal appears to be crucial since no nanorod formation took place in the absence of it. The products were characterized by FTIR spectroscopy, X-ray diffraction and transmission electron microscopy (TEM).