Polyvinyl alcohol (PVA)/ammonium molybdate composite fibers were prepared by using sol-gel processing and electrospinning technique. After calcinations of the above precursor fibers at 500 degrees C, MoO3 nanofibers with a diameter of 100-150 nm were successfully obtained. MoO3 nanoplatelets and submicron platelets were prepared by further calcinations of the MoO3 nanotibers at 600 and 700 degrees C. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). A possible growth mechanism for the MoO3 nanofibers and nanoplatelets was suggested. (c) 2006 Elsevier Ltd. All rights reserved.