Abstract: Shape-control has been much more difficult to be achieved in the synthesis of nanoparticles. For the aim to establish whether a favorable combination of functional organic molecules and inorganic precursors might produce predictable particle morphology, several carboxy-containing organic compounds, such as acetic acid(AcOH), acetoacetic ester(EAA), poly(amidoamine)dendrimer(PAMAM) and the like, have been investigated in both organic solvent and aqueous solution in the synthesis of Al₂O₃ nanoparticles from aluminium alkoxide and aluminium nitrate precursors, respectively. The spherical particles with different sizeranges(<10 nm, 20-40 nm, 50-100 nm), and the fibrous with changed aspect ratios(from 100 nm/4 nm to 10 nm/4 nm) were observed and characterized, whose distribution was dependent on the property of organic compounds and its concentration used. Apossible shapecontrol mechanism was proposed and discussed.

Key words: Alumina, Shape-control, Nanoparticle