Controlled synthesis of nanomaterials using reverse micelles

Abstract

Monophasic nanosized oxides were synthesised mainly from metal oxalate nanorods obtained using the reverse micellar method. This paper focuses on the methodology to obtain important metal oxides like tin dioxide, cerium oxide (CeO₂ ), zirconia, and zinc oxide. The effect of oxidationstate of the metal ion on the morphology of the oxalates was studied. Nanorods of zinc (II) oxalate (120 nm in dia and 600 nm in length) were obtained while spherical particles of size 4. 6 nm were obtained for cerium (III) oxalate. The decomposition of these precursors at higher temperature led to the formation of their respective oxides. Mixture of nanorods and nanoparticles of CeO₂ was obtained while 3.4 nm sized ZrO₂ nanoparticles were obtained by thermal decomposition of zirconium oxalate precursor. The dielectric constant and loss were highly stable with frequency (at room temperature) for both ceria and zirconia nanoparticles. ZnO nanoparticles (55 nm sized) were obtained by the decomposition of zinc oxalate nanorods. Three peaks corresponding to free excitonic emission, free-to-bound, and donor-acceptor transitions were observed in the photoluminescence studies at 20 K for ZnO nanoparticles.