Effect of Temperature Sintering on Grain Growth and Optical Properties of TiO2 Nanoparticles

Abstract

Titanium dioxide (TiO2) nanoparticles were prepared by the sol–gel method and the structural, morphological, and optical properties were investigated at different sintering temperatures of 500, 600, 700, 800, and 900°C. A tetragonal structure of anatase, mixed (anatase–rutile), and rutile phases are observed in the X-ray diffraction (XRD) analysis. Pure anatase phase formation occurred at 500°C, whereas anatase-to-rutile phase transformation began at 600°C, and reaching complete conversion to rutile at 800°C. The average crystallite size increased from 23 to 34 nm for anatase and 38 to 62 nm for the rutile when sintering temperature increased from 500 to 900°C. The scanning electron microscope (SEM) result presented the increase of grain size (25–100 nm) with increasing the sintering temperature. The Fourier transform infrared (FTIR) spectra demonstrated the presence of TiO2 vibrational bonds in all samples. The optical bandgaps of the sintered TiO2 nanoparticles decreased with rising sintering temperature. Photoluminescence spectra exhibited three characteristic peaks centered at 380, 450, and 550 nm. The emission intensity increased with increasing the sintering temperature. The Mie analysis was also studied to calculate scattering cross-section, forward scattering, and asymmetry for different grain sizes. The results showed that by increasing the nanoparticle diameters, the peaks of all spectra are redshifted for larger grain sizes and cross-section peaks shift to high values. In this study, the sintering temperature is observed to have a strong influence on crystalline phase transformation, microstructure, and optical properties of TiO2 nanoparticles. The TiO2 sample sintered at 900°C shows the best result to be used as luminescent material due to the low optical bandgap energy.

Freeze casting of hydroxyapatite‐titania composites for bone substitutes

“…82,83 Through the combined HA and TiO 2 solid loading, smaller grain size and the presence of interfacial bonding are occurring in the composite scaffolds. Combined with the EDX analysis which showed more evenly distributed regions of calcium and titanium in HT-50 samples, lower mechanical properties in HT-25 and HT-75 were thus attributed to larger grain sizes 79,80,82 from sintering and fewer interfacial boundaries 83,84 from the composite loading as previously reported. In contrast, the better balance of HA and TiO 2 in HT-50 led to a more optimal combination of the factors that resulted in stronger scaffold when sintered at 1250 C. [82][83][84] As suggested, the TiO 2 content therefore increased the UCS and E compared to HA alone and reached an experimental maximum in HT-50 with a UCS of 3.12 ± 0. are not shown as they showed much greater cell activity in comparison to the scaffold samples.…”

“…78 The grain size of rutile TiO 2 has been found to increase with sintering temperature from 500 to 900 C, which would also mean further grain growth at higher sintering temperatures like that used in this study (1250 C). 79,80 For HA which is naturally brittle, 10,81 doping is often used to mitigate this less desirable trait. 75 Doping of TiO 2 with calcium and strontium ions was also reported to both reduce grain size and provide interfacial bonding 64 at grain boundaries which increased mechanical strength.…”

Fabrication and Characterization of TiO2 Coatings on 304 Stainless-Steel Substrate for Efficient Oil/Water Separation

“…This process was repeated twice for mesh sizes 100 and 200. Sintering at 450 • C was expected to retain the anatase phase of TiO 2 , as a comparable temperature (500 • C) has been studied among temperature ranges between 500 to 900 • C [31]. Temperatures greater than 900 • C have been proposed as anataserutile phase transition temperatures for metastable TiO 2 [32].…”