Formation and growth of anatase TiO2 nanocrystals under hydrothermal conditions

This work is devoted to the study of the processes of formation and growth of TiO2 nanoparticles under hydrothermal conditions. TiO2 nanocrystals were obtained during the dehydration of hydrated titanium dioxide by varying the temperature and duration of hydrothermal treatment, as well as the method of precipitation of the synthesis precursor. The study of various characteristics of the synthesized TiO2 nanoparticles by PXRD, SEM, TEM, and low-temperature nitrogen sorption made it possible to propose mechanisms for the formation of crystalline titanium dioxide from an X-ray amorphous precursor and the growth of titanium dioxide nanocrystals with an anatase structure under hydrothermal conditions. Within the scope of the chosen model of oriented attachment, the dependence of the sizes of TiO2 crystallites on the parameters of hydrothermal synthesis is mathematically described. It was concluded that the direct precipitation of the synthesis precursor from titanium tetrachloride is superior to the reverse. It is shown that the temperature of hydrothermal treatment largely determines the size and morphology of the formed crystallites and TiO2 nanoparticles, the rate of the crystallization process, and the preferred mechanisms of nanocrystal growth, while the duration of synthesis affects the agglomeration processes and the specific surface area of titanium dioxide powders.

Automated summary

This study focuses on the formation and growth of TiO2 nanoparticles under hydrothermal conditions. TiO2 nanocrystals were synthesized by dehydrating hydrated titanium dioxide at different temperatures, durations, and precipitation methods for the synthesis precursor. Various characteristics of the synthesized nanoparticles were investigated, and mechanisms for the formation of crystalline titanium dioxide and the growth of anatase structured titanium dioxide nanocrystals under hydrothermal conditions were proposed. The size of TiO2 crystallites was mathematically described based on the chosen model of oriented attachment. The study also revealed the superiority of direct precipitation from titanium tetrachloride as the synthesis precursor and the influence of hydrothermal treatment temperature and synthesis duration on the size, morphology, crystallization rate, agglomeration processes, and specific surface area of the TiO2 nanoparticles.