Microwave-assisted synthesis of nanocrystalline ZnWO4 powders via a water-based citric acid complex precursor

Nanocrystalline ZnWO4 powders were successfully synthesized from a water-based citric acid complex precursor using microwave irradiation. The polymeric precursors were heat treated at temperatures from 300 to 600 degreesC for 3 h. Crystallization of the ZnWO4 was detected at 400degreesC and entirely completed at a temperature of 600degreesC. The powders at 400 and 500degreesC showed primarily a co-mixed morphology with spherical and silkworm-like forms. The powders at 500degreesC had a relatively more homogeneous morphology, while the powders at 600degreesC showed a relatively exaggerated growth a including rectangular form. The average crystalline sizes were 18similar to25 our, showing an ordinary tendency to increase with temperature from 400 to 600degreesC.