Study of the role of metal core on the thermal behavior of Ag@TiO2 core–shell nanoparticles

Thermal behavior of the TiO₂ shell in the core–shell Ag@TiO₂ system has been investigated by the time differential perturbed angular correlation (TDPAC), transmission electron microscope and X-ray diffraction measurements in the temperature range from 473 to 1073 K. Although the thickness of the TiO₂ shell increases on annealing, the TDPAC results show that the anatase phase persists till 1073 K. This is in contrast with the results for the pure TiO₂ nanoparticles. These observations suggest that the phase transformation from anatase to rutile is hindered in case of core–shell nanoparticles possibly because the growth of the shell thickness in case of Ag@TiO₂ nanoparticles is not effective for rutile formation due to the presence of Ag-core.