Heating-Induced Transformation of Anatase TiO₂ Nanorods into Rock-Salt TiO Nanoparticles: Implications for Photocatalytic and Gas-Sensing Applications

Abstract

Anatase TiO 2 nanocrystals (NCs) play a vital role in photocatalytic applications due to their high catalytic activity and in gas-sensing applications due to their high chemical sensitivity. Here, we report the transformation at elevated temperature of anatase nanorods (NRs) with a length of 25 nm into rock-salt TiO nanoparticles with an average size of 9.2 ± 2.1 nm investigated by means of in situ heating in the transmission electron microscope. The NRs were completely transformed to titanium monoxide NCs after heating to a temperature of 1200 °C. We also identified an intermediate stage in the temperature range of 950–1200 °C, during which not only the anatase and rock-salt phases were found but also the brookite phase. Understanding of the phase and morphology evolution at high temperatures is of essence to the functionality of the NRs in various applications, as discussed in this work. Moreover, the high-temperature transformation to titanium monoxide is of interest as rock-salt TiO (γ-TiO) is known to exhibit superconducting properties. We propose the heating-induced transformation as a physical route to synthesize TiO NCs of very small size.

Synergistic Effect of Nickel Nanoparticles Dispersed on MOF-Derived Defective Co3O4 In Situ Grown over TiO2 Nanowires toward UV and Visible Light Driven Photothermal CO2 Methanation

“…Consequent thermal treatment into 10Ni-Co 3 O 4 @TiO 2 NWs-I also showed characteristic peaks of TiO 2 NWs, with an additional brookite peak observed at 30.9°. The presence of the additional brookite peak together with the anatase/brookite peaks was due to the continuous thermal treatment of the catalyst, as reported in previous studies, where calcination in air induced the transformation of anatase to brookite. , Similarly, Christoforidis et al reported that the calcination of H-titanate at 380 °C retained the 1D fibril morphology but led to the formation of the brookite phase . Nevertheless, the ternary 10Ni-7Co 3 O 4 /TiO 2 NWs-M nanocomposite prepared via the mechanical assembly method displayed the peaks of both TiO 2 NWs and Co 3 O 4 .…”

“…The presence of the additional brookite peak together with the anatase/brookite peaks was due to the continuous thermal treatment of the catalyst, as reported in previous studies, where calcination in air induced the transformation of anatase to brookite. 15,16 Similarly, Christoforidis et al reported that the calcination of H-titanate at 380 °C retained the 1D fibril morphology but led to the formation of the brookite phase. 17 Nevertheless, the ternary 10Ni- According to Figure 1b, ZIF-67 is identified as a microporous material because it exhibits a type I isotherm.…”

Fibrous TiO2 Alternatives for Semiconductor-Based Catalysts for Photocatalytic Water Remediation Involving Organic Contaminants

“…X-ray diffractograms reveal that all materials are composed of the anatase crystalline phase, which is the most photocatalytically active. − The position of the peaks at 2θ = 25.4, 37.9, 48.1, 55.05, 55.2, and 62.9° correspond to the respective planes (101), (004), (200), (105), (211), and (204) of tetragonal anatase TiO 2 (JCPDS: 01-073-1754), Figure A. Using the Scherrer equation, we calculated the crystalline sizes of the photocatalysts finding 13.2, 10.3, and 9.5 nm for TNF, TGW, and TGF, respectively.…”

Insights into the Photocatalytic Memory Effect of Magneto-Plasmonic Ag–Fe3O4@TiO2 Ternary Nanocomposites for Dye Degradation and H2 Production under Light and Dark Conditions

“…The peaks corresponding to Fe 3 O 4 and Ag along with TiO 2 in the XRD patterns of Fe 3 O 4 @TiO 2 and Ag−Fe 3 O 4 @ TiO 2 clearly indicate their crystalline phase formation in the composite. It is revealed from the matched JCPDS data that the phase of the formed TiO 2 is anatase with a tetragonal 17,18 crystal system. The crystal structures of Fe 3 O 4 and Ag are found to be inverse cubic spinel 19 and cubic, 20 respectively.…”