Synthesis of TiO2−MgO mixed metal oxide nanoparticles via a sol−gel method and studies on their optical properties

TiO2−MgO mixed metal oxide nanoparticles with variable MgO content were prepared by a simple sol−gel method. The nanoparticles were characterized by power X-ray diffraction, field emission scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy and UV−visible diffuse reflectance spectroscopy. X-ray diffraction results indicate that the presence of MgO prevents the complete transformation of anatase to rutile in the TiO2−MgO mixed metal oxide nanoparticles prepared using lower MgO content even at 900 °C. The presence of MgO in TiO2−MgO nanoparticles suppresses the crystal growth of TiO2 leading to a blue-shift of its band gap. The TiO2−MgO samples prepared using higher MgO content and calcined at 700 °C and 900 °C lead to mixed metal oxide nanoparticles with high band gap (~4.3 eV) due to the formation of MgTiO3.