Raman spectroscopy as a tool for the elucidation of nanoparticles with core–shell structure of TiO2 and MoO3

In this work, we report the synthesis of TiO2 nanoparticles and core–shell TiO2–MoO3 and MoO3–TiO2 nanoparticles dispersed into porous Vycor glass by the metallo-organic decomposition process (MOD). The nanoparticles were analyzed using Raman spectroscopy by monitoring the E2g band (phonons region for anatase TiO2) and the bands located at 820 and 996 cm−1 (vibrational modes of α-MoO3) when Mo is present. The diameters of the TiO2 nanoparticles dispersed in the glass matrix were calculated by means of the phonon confinement model and the values obtained are 3.9, 4.6, and 5.7 nm depending on the number of impregnation–decomposition cycles used in the nanoparticle syntheses.