The Role of Oxygen Vacancy in Anatase to Rutile Transformation of TiO2

Titanium dioxide (TiO2) recently has attracted a great deal of attention in different fields, such as renewable energy and pollutant removal, due to its low price and amphoteric nature. Many studies have pointed out that phase composition and oxygen vacancies play a certain role in promoting the performance of TiO2. However, the effect of oxygen vacancy on the phase transformation of TiO2 has been ignored, which also influences the phase composition and limits its application under certain conditions. In this paper, by controlling the univariate of oxygen vacancy, the influence of oxygen vacancy on the stability and crystal type of TiO2 is clearly pointed out, with the help of variable temperature in situ X-ray diffraction, differential thermal analysis (DTA), and discrete Fourier transform (DFT) theoretical calculations. The formation of oxygen vacancy can reduce the phase-change energy, which must be overcome before rearrangement of the structure, and promote the phase transformation of anatase. Based on these, it also provides a guide for the design of materials with oxygen vacancy.