Preparation and characterization of V2O3 micro-crystals via a one-step hydrothermal process

Phase pure V2O3 micro-crystals with a hexagonal dipyramid morphology were fabricated for the first time via a facile one-step hydrothermal method. The crystals were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). A hexagonal dipyramid structure of V2O3 enclosed by well-grown {012} facets was obtained by hydrothermally reducing VO(acac)2 precursor with N2H4·H2O at 220 °C for 48 h. The results indicated that V2O3 can be well crystallized up to micron size with distinguished facets by only one step hydrothermal treatment. The formation mechanism and morphology evolution for V2O3 micro-crystals were discussed. Based on our experiments, the V2O3 nuclei formed and grew by a phase transformation through a dissolution–recrystallization process of VOOH, and the formation of the hexagonal dipyramids was ascribed to the specific adsorption of Hacac to the {012} facets restraining the growth in the directions normal to the {012} facets. The present work provides a facile method for preparing phase pure V2O3 micro-crystals with hexagonal dipyramid morphology, which can be used as a new powder material for ceramic fabrication.