OPTIMIZATION OF THE SURFACE AREA OF V2O5 NANOCRYSTALS THROUGH NUMBER OF WASHING

Abstract

In this study, vanadium pentoxide, V₂O₅ were synthesized by precipitating ammonium vanadate with ammonium hydroxide in increasing pH method. The solid precipitates obtained were then subjected to different number of washing and its effect on the microstructural properties of V₂O₅ was studied. TGA result suggested that 500 °C was the best temperature to transform the precursor into the desired products. This has been confirmed by the XRD result of calcined samples which showed diffractograms matched perfectly with V₂O₅ phase. The V₂O₅ particles sizes were in nanometre range between 24 – 62 nm. SEM morphology revealed that the particles showed rectangular shape before and after calcined with holes and cracks surfaces compared to a rather smooth surface in the precursor. This suggested that upon heat treatment, all the impurities have been successfully eliminated and in doing that, they left holes and cracks. Specific surface area, S_BET of the unwashed sample gave highest value         (6.1m²g^-1 ) compared to the others samples. The low S_BET value for the latter sample was probably due to peptization process occurred during the washing step.