Size dependence of rutile TiO2 lattice parameters determined via simultaneous size, strain, and shape modeling

Simultaneous crystal structure, microstructure, and morphology modeling with convolution-based profile fitting of angle-dispersive synchrotron x-ray diffraction data was applied to retrieve the size-dependent lattice changes in nanocrystalline rutile TiO2. The dominant prismatic crystallite morphology was adequately modeled using the parallelepiped geometry. As with anatase TiO2, opposing trends of decreasing c and increasing a parameter, as well as lattice expansion with decreasing average crystallite size were observed. A correlation between Ti vacancy abundance and lattice volume increase suggests a possible causative link.