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.