Preparation and characterization of (V1−xAlx)2O3 ultrafine powders by chemical doping method

(V_1−xAl_x)₂O₃ ultrafine powders have been synthesized successfully by pyrolysizing poly-crystalline Al-doped precursor, Al-doped (NH₄)₅[(VO)₆(CO₃)₄(OH)₉]·10H₂O in H₂ atmosphere at 1373 K for the first time. The relation between the ratio of Al/V in the VOCl₂ solution and that in polycrystalline Al-doped precursor was studied. The result shows that this chemical doping method is successful, and the Al (III) content in precursor is controllable. The lattice parameters of (V_1−xAl_x)₂O₃ determined by XRD at room temperature and high-temperature reveal that the Al (III) enter the V₂O₃ lattice. The SEM micrograph shows that the size of the powder particles is about 100-200 nm. The DSC and magnetic susceptibility results of the (V_1−xAl_x)₂O₃ demonstrate that the powders exhibit the intrinsic phase transition properties.