High bismuth content Bi-MCM-41: Synthesis, characterization and investigation on the distribution of bismuth atoms

Bismuth containing MCM-41 with high Bi content (8.3 wt%, 10.3 wt%, 12.2 wt %, 14.5 wt %) was directly synthesized in strongly acidic media. The characterization of PXRD (Powder X-ray diffraction) and N2 adsorption/desorption conformed that the samples have typical MCM-41 channel structure, and UV–vis (Diffuse reflectance UV–visible spectroscopy) and Raman analyse revealed that all bismuth atoms were highly dispersed in the silica-based framework structure. XPS (X-ray photoelectron spectroscopy) analyse suggested that the distribution of bismuth atoms in the samples is not uniform entirely, and the content of Bi in Bi-MCM-41 maybe degressive from the internal surface to external surface under the given synthesis conditions. Furthermore, it was found that the binding energy of Bi4f7 and Bi4f5 are decreased with the Bi content of MCM-41 increasing.