Microstructural view of anatase to rutile phase transformation examined by in-situ high-temperature X-ray powder diffraction

Effect of TiO2 on the thermal performance and emissivity of glass coatings

“…26 Thus, the anatase phase exhibited an average emissivity of 0.84, and the rutile phase showcased an average emissivity of 0.78 within the 7 μm to 15 μm wavelength range. The contents of both phases were determined using the adiabatic method, 27 which was calculated by eqn (5): 28 I 1 and I 2 represent the peak diffraction intensities of the test material phases, and K 1 c and K 2 c represent the reference intensities of the test material phases, known as the K -values.…”

Improvement of Photocatalytic Performance by Building Multiple Heterojunction Structures of Anatase–Rutile/BiOI Composite Fibers

“…The submicron sheet clusters would not interfere with each other, and TiO 2 should not be excessively shaded by BiOI, which can be observed by SEM images. With the increase in the concentration of BiOI, the E g characteristic peak of TiO 2 at 143 cm −1 has a red shift to 141.3 cm −1 , and the E g peak at 636.3 cm −1 has a blue shift to 638.1 cm −1 , this indicates that the lattice structure of TiO 2 has been distorted [ 38 ], and lattice distortion is the main factor for the generation of heterojunctions.…”

Black TiO2 and Oxygen Vacancies: Unraveling the Role in the Thermal Anatase-to-Rutile Transformation

“…The thermal anatase-to-rutile transition is not just a mere phase transformation but a gateway to understanding and harnessing the true potential of TiO 2 in various applications [9]. However, the criticality of the anatase-to-rutile transition remains a subject of intensive debate, primarily due to the varying transition temperatures and its reconstructive atom bond mechanism influenced by nanocrystal size, impurities, annealing temperature, and synthesis conditions [9,10]. As an example, very recently advanced characterization techniques such as ATR-FTIR, EELS, EFTEM imaging, XPS, Raman spectroscopy, and DRIFTS have confirmed the successful doping of the TiO 2 nanoparticles with nitrogen, phosphorus, and carbon [11].…”

“…Despite the extensive literature on the TiO 2 phase transformation, a significant gap exists in understanding the temperature dependence of unit cell parameters and microstructure. Previous studies have predominantly used ex situ powder X-ray diffraction (XRD) to determine these parameters [14], but this may yield less reliable outcomes due to the loss of thermally triggered lattice features upon cooling [10]. On the other hand, in situ XRD methods offer a more accurate picture of phase transformation and the available studies on the thermal behavior of anatase in air have indicated a linear expansion of unit cell parameters with increasing temperature [15].…”

“…However, these investigations are confined to temperatures below the phase transition threshold, thereby limiting insights into lattice alterations during phase transformation. Recently, an in situ powder diffraction study with Cu source on a commercial P25 sample, a 85:15 mixture of anatase and rutile nanoparticles (NPs), revealed really unusual properties across the anatase-to-rutile phase transition [10]. Notably, an average negative thermal expansion of the anatase c-axis was observed accompanied by the decrease in particle size with increasing temperature in the temperature range of 673 ≤ T ≤ 973 K [10].…”