Properties of nanocrystalline TiO2 synthesized in premixed flames stabilized on a rotating surface

Memarzadeh, Saro; Tolmachoff, Erik D.; Phares, Denis J.; Wang, Shuangfeng

doi:10.1016/j.proci.2010.05.065

Cited by 40 publications

(54 citation statements)

References 40 publications

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“…Titania nanoparticles are prepared using af lame CVD technique. [27,29,43] As illustrated in Figure 1, aq uasi 1D disc-like gaseous flame sheet is stabilized at atmospheric pressure around 3mm from ar otating surface. The mechanism of flame stabilization is flow stretch or anchoring of the flame due to gas flow divergence as it impinges against the surface.…”

Section: Experimental Methodsmentioning

confidence: 98%

“…Titania nanoparticles are prepared using a flame CVD technique . As illustrated in Figure , a quasi 1D disc‐like gaseous flame sheet is stabilized at atmospheric pressure around 3 mm from a rotating surface.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…It is worthy noting that the actual peak temperature of the synthesis flame is lower than the adiabatic flame temperature because of heat loss to the rotating surface. For example, the actual temperature is around 2100 K for flame 1a, while the adiabatic flame temperature is 2354 K …”

Section: Experimental Methodsmentioning

confidence: 99%

“…A series of flame synthesis studies we conducted over the past years suggest that the phase equilibrium of TiO 2 nanocrystals cannot be fully described by Banfield's model. Although the earlier results are not as conclusive owing to the limited range of gas conditions in which rutile was found to be dominant, these studies did show that rutile particles <14 nm and anatase particles >14 nm can be reproducibly prepared in flames . The determining factor appears to be the gas‐phase composition and more specifically, the availability of molecular oxygen.…”

Section: Introductionmentioning

confidence: 99%

“…Althought he earlier results are not as conclusive owing to the limitedr ange of gas conditions in which rutile was found to be dominant, these studies did show that rutile particles < 14 nm and anatase particles > 14 nm can be reproducibly prepared in flames. [13,27,28] The determining factor appears to be the gas-phase compositiona nd more specifically,t he availability of molecular oxygen.W hile anatase was the dominant crystal phase in oxygen-rich conditions, rutile was predominant in oxygen-deficiente nvironment. Similar observations were reported in co-flow diffusion flamesi nw hich controlled quenching led to somed egree of controlled titania nanoparticle crystal phase.…”

Section: Introductionmentioning

confidence: 99%

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Phase Equilibrium of TiO₂ Nanocrystals in Flame‐Assisted Chemical Vapor Deposition

2017

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Nano-scale titanium oxide (TiO ) is a material useful for a wide range of applications. In a previous study, we showed that TiO nanoparticles of both rutile and anatase crystal phases could be synthesized over the size range of 5 to 20 nm in flame-assisted chemical vapor deposition. Rutile was unexpectedly dominant in oxygen-lean synthesis conditions, whereas anatase is the preferred phase in oxygen-rich gases. The observation is in contrast to the 14 nm rutile-anatase crossover size derived from the existing crystal-phase equilibrium model. In the present work, we made additional measurements over a wider range of synthesis conditions; the results confirm the earlier observations. We propose an improved model for the surface energy that considers the role of oxygen desorption at high temperatures. The model successfully explains the observations made in the current and previous work. The current results provide a useful path to designing flame-assisted chemical vapor deposition of TiO nanocrystals with controllable crystal phases.

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Section: Experimental Methodsmentioning

confidence: 98%

Section: Experimental Methodsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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