Bismuth-doped tin dioxide (BTO) nanometer powders were prepared by the wet chemical method using tin tetrachloride (SnCl4)

bismuth nitrate ［Bi(NO3)3］ and ammonia as raw materials. Non-bridge hydroxides and capillary force between particles were found to be key factors causing hard aggregation of BTO through analyzing the formation mechanism of hard aggregation. The hard aggregation of BTO was eliminated effectively when the Bi-Sn precursor (BSP) was treated with post processing including dispersing with ultrasonic wave

refluxing and distilling with addition of n-butanol and benzene (DRD) and drying by microwave. Characterized with X-ray diffraction (XRD) and transmission electron microscopy (TEM)

BTO spherical particles with tetragonal phase structure are well crystallized

dispersed easily and the average size was less than 10 nm.