Observing the formation of TiO2 mesocrystals from NH4TiOF3 microparticles using in situ thermo-WAXS measurements

Real-time in situ X-ray analysis was used to shed light on the topotactic transformation of NH₄TiOF₃ into nanostructured TiO₂ mesocrystals. Specifically, for the system formed in the presence of the PEG-2000 templating polymer, XRD analysis showed that the overall transformation occurs through four separate transitions, consistent with previous reports. The applicability of synchrotron wide-angle X-ray scattering (WAXS) to real-time in situ analysis has enabled precise temperature mapping of these four transitions and the identification of stability boundaries for the first time.