Crystal quality and optical property of MnWO₄ nanoparticles synthesized by microwave-assisted method

MnWO₄ nanoparticles were prepared using a microwave-assisted method followed by low-temperature treatment. The crystal quality and optical property of the MnWO₄ nanoparticles were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, and ultraviolet-visible (UV-vis) absorption spectroscopy. Our results show that good crystal quality MnWO₄ nanoparticles can be prepared by the microwave-assisted method, and best crystal quality nanoparticles can be obtained with synthesizing pH value of 7. Furthermore, by calcination treatments, crystal quality can be further improved with less defect states and the particle size increases when the calcining temperature increases from 150 to 600 °C. In addition, our study shows that the MnWO₄ nanoparticles have strong absorption in the visible light region, suggesting that these nanoparticles are promising for photocatalytic applications.