Controlled synthesis of semiconductor PbWO4 nanocrystals inside silica SBA-15 materials

A new flexible approach is developed to synthesize PbWO₄ nanoparticles inside the channels of mesoporous silica SBA-15. Mesoporous SBA-15 silica with 7 nm pores was produced by a hydrothermal process and used as a hard template. PbWO₄ nanoparticles were synthesized and incorporated into the mesoporous silicate support in a low-power ultrasonication condition. The as-synthesized samples were characterized by Raman spectroscopy, diffuse reflectance UV–vis spectroscopy (UV–vis), powder X-ray diffraction (XRD), small-angle X-ray diffraction (SAXRD), nitrogen adsorption and transmission electron microscopy (TEM). It was found that PbWO₄ nanoparticles appeared among the channels of SBA-15. Blue shift was observed in UV–vis absorption spectra due to the quantum size effect of PbWO₄ nanoparticles. This preparation method is also capable of synthesis of various semiconductor nanoparticles with controlled size and morphology inside the channels of mesoporous materials.