Nucleation and growth of self-assembled nanofibre-structured rutile (TiO2) particles via controlled forced hydrolysis of titanium tetrachloride solution

Charbonneau, Cécile; Gauvin, Raynald; Demopoulos, George P.

doi:10.1016/j.jcrysgro.2009.09.033

Cited by 38 publications

(36 citation statements)

References 27 publications

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“…The diameter of the nanofibers forming the pinecone-like and spherical clusters was nearly 10 nm and remained almost constant independent of the reactant concentration. However, an increase in the initial concentration of the reactant solution increased the length of the nanofibers similar to the results reported by Sun et al [39] and Charbonneau et al [40].…”

Section: Effect Of the Concentration Of Ticl 4 Solutionsupporting

confidence: 89%

“…The time for the formation of the nuclei, observed visually from the change in the transparency of the solution, increased when the reaction temperature decreased from 95 to 60°C. This time lag caused an increase in the crystallite size due to the slow hydrolysis reaction at low reaction temperatures and an instantaneous formation of nuclei with a small crystallite size at high reaction temperatures as in the case of the study conducted by Charbonneau et al [40].…”

Section: Effect Of Reaction Temperaturementioning

confidence: 91%

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Visible light photocatalytic activity of rutile TiO2 fiber clusters in the degradation of terephthalic acid

Yener

Helvacı

2015

Appl. Phys. A

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Rutile TiO 2 nanoparticles, in different structural and morphological properties, were produced by the hydrolysis of titanium tetrachloride in a highly acidic reaction media at moderate temperatures without calcination. Their photocatalytic activities were investigated in the liquid-phase degradation of terephthalic acid under visible light illumination. The parameters, which are the concentration of the titanium tetrachloride solution (0.1-1 M) and reaction temperature (60-95°C), effective on the properties of the particles, and their photocatalytic performances, were investigated. The XRD patterns indicated a pure rutile crystal structure at moderate temperatures without need of calcination. The FEGSEM images showed the formation of flower-, pinecone-, and sphere-like clusters consisting of interconnected nanofibers. The N 2 adsorption-desorption isotherms pointed out the microporous structure of the clusters. Band gap energies were found to be varying between 3.02 and 3.08 eV due to the well-developed rutile crystallite structure. Systematic studies elucidated that the optimum reactant concentration and reaction temperature are 0.5 M TiCl 4 and 95°C, respectively. The rutile clusters synthesized at the optimum reaction conditions exhibited 99 % of the photocatalytic degradation of TPA under visible light illumination at shorter irradiation times compared with commercial P25 TiO 2 .

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Section: Effect Of the Concentration Of Ticl 4 Solutionsupporting

confidence: 89%

Section: Effect Of Reaction Temperaturementioning

confidence: 91%

Visible light photocatalytic activity of rutile TiO2 fiber clusters in the degradation of terephthalic acid

Yener

Helvacı

2015

Appl. Phys. A

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“…23 The general chemical reaction describing the hydrolytic conversion of TiCl 4 to TiO 2 is given in Eq. 1…”

Section: Resultsmentioning

confidence: 99%

Aqueous Solution Synthesis of Crystalline Anatase Nanocolloids for the Fabrication of DSC Photoanodes

Charbonneau

Gauvin

Demopoulos

2011

J. Electrochem. Soc.

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The production of anatase nanocolloids via a novel aqueous solution synthesis method is described. The process involves forced hydrolysis of 0.2 M TiCl 4 aqueous solution at low temperature ͑80°C͒ leading to fast nucleation of TiO 2 anatase nanoparticles ͑4-5 nm͒. The isolated nanopowders were found to consist predominantly of anatase as the major phase ͑ ϳ 85 wt %͒, possess a very high surface area ͑up to 250-350 m 2 /g͒, and a relatively elevated surface hydroxyl content in comparison with the P25 reference material. Single-layer ͑ϳ12 m thick͒ photoanodes prepared with aqueous-synthesized powders were found to have a specific surface area of ϳ130 m 2 /g and the anatase nanocrystallites to have grown to ϳ12 nm and assume a higher degree of crystallinity but still carry ϳ1.5% surface OH groups. The pore size of the film was determined to be ϳ8 nm. By comparison, the film prepared with P25 nanoparticles had the following properties: 50 m 2 /g, 30 nm crystallite size, 0.2% surface OH, and 25 nm pore size. Dye-sensitized solar cell ͑DSC͒ devices assembled with the newly fabricated photoanodes showed equivalent photoelectrochemical performance ͓power conversion efficiency , short-circuit current voltage I sc , open-circuit voltage V oc , and Fill Factor ͑FF͔͒ to cells prepared using the benchmark P25 titania powder.The synthesis of nanostructured TiO 2 powders for the fabrication of mesoporous photoanodes in dye-sensitized solar cells ͑DSCs͒ has been widely investigated in the last decade. 1 The light-to-current conversion yield of such device is known to depend on a number of parameters, including the properties of the TiO 2 powder material used for the fabrication of the photoanode. Among these properties, particle size and morphology, 2-4 crystallinity, phase content, 5,6 bandgap, 4 chemical composition ͑doping͒, 7 and surface groups 8,9 have been extensively studied and shown to have a significant bearing on the overall efficiency of the DSC devices.Different methods have been developed for the synthesis of TiO 2 particles with properties suited for the fabrication of photoanodes. Among these is the two step sol-gel/hydrothermal synthesis process: 10-12 a titanium alkoxide-based solution ͑usually titanium tetraisopropoxide or butoxide in ethanol͒ is first hydrolyzed to form amorphous TiO 2 powders; crystallization is then induced in an autoclave at high pressure and temperature ͑typically 250°C͒. This method has been successfully developed for the preparation of anatase TiO 2 nanoparticles ͑10-30 nm͒ with large surface area ͑80-150 m 2 /g͒. 13 However, sol-gel processing, especially some complex variations of it, 14 is chemical and energy intensive, multistep, and time-consuming and so does not lend itself to easy scale-up and cost-effective operation. The P25 TiO 2 powder from Degussa ͑20% rutile, 80% anatase, 50 m 2 /g, 30 nm average particle size͒, which is considered a reference material among the commercially available nanostructured TiO 2 powders, is produced by flame synthesis. 15 This process, although ef...

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“…However, advances in aqueous-based synthesis of TiO 2 may provide commercially scalable synthesis routes for not only anatase nanoparticles [12], but other phases and morphologies of TiO 2 [116,117] …”

Section: Anatasementioning

confidence: 99%

Novel Mesoporous Nanotitania/Carbon Composite Electrodes for Electrochemical Energy Storage

et al. 2013

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The development of novel scalable nanoscale materials and fabrication techniques for high performance TiO 2 Li-ion electrodes is investigated in this thesis. The development and study of the novel fabrication methods is approached from the stand point of a binder-free electrode, and its comparison to standard binder-based electrodes, making use of commercial P25 TiO 2 product as active material. The characterization of novel titania synthesized by manipulating the parameters of an aqueous process, is performed for two phases of TiO 2 , namely anatase and brookite, based on comprehensive nanocrystal morphological and electrochemical property assessment. Finally all is brought together by investigating the application of the novel fabrication protocol to the aqueous synthesized anatase to engineer binderfree 3-dimensional electrodes, and studying their Li-ion intercalation performance.The fabrication of binder-free P25 nanotitania/carbon composite electrodes is pursued via formulating pastes and controlled sintering yielding enhanced electrochemical performance in comparison to standard binder-based methods using the same active and conductive components. The new paste formulation and sintering sequence provides a significant increase in dispersion of carbon due to smaller agglomerate size resulting in enhanced inter-particle (active-conduction) mixing and packing density than standard binder-based electrodes. Cyclic voltammetry and galvanostatic charge/discharge proved that the binder-free electrodes possess improved conductivity, specific capacity, and reversibility, as compared to binderbased electrodes. Most significantly, the capacity retention of the binder-free electrode was much higher than that of the binder-based electrode at 94 and 53%, respectively.iii Using an aqueous solution based synthesis process, 2-dimensional brookite nanoplatelets and 6 nm anatase nanoparticles are obtained and examined for their physical and electrochemical properties as Li-ion host materials. Brookite, itself is particularly interesting, as it is the least understood of the nanoscale TiO 2 phases, especially in the form of 2-D crystal structures that are deemed advantageous for Liion diffusion. This study provides insight into the lithiation mechanism of brookite, concluding that a solid-solution is formed upon lithiation corresponding to Li 0.5 TiO 2 that is isostructural with brookite. Further, the brookite nanoplatelets are discovered to undergo unique crystal structure enhancement upon cycling that allows them to quickly relax upon delithiation in an extremely efficient (>99.7% Coulombic efficiency) reversible manner translating to excellent Li-ion intercalation stability.Anatase nanoparticle are described in terms of crystallinity and surface area. Asprepared anatase has low crystallinity (∼70%), but high surface area (∼222 m 2 g −1 ), and when annealed at 300°C, the crystallinity increases to ∼90% but the surface area drops to 120 m 2 g −1 . Electrochemically, this allows the annealed sample with higher crystall...

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Nucleation and growth of self-assembled nanofibre-structured rutile (TiO2) particles via controlled forced hydrolysis of titanium tetrachloride solution

Cited by 38 publications

References 27 publications

Visible light photocatalytic activity of rutile TiO2 fiber clusters in the degradation of terephthalic acid

Visible light photocatalytic activity of rutile TiO2 fiber clusters in the degradation of terephthalic acid

Aqueous Solution Synthesis of Crystalline Anatase Nanocolloids for the Fabrication of DSC Photoanodes

Novel Mesoporous Nanotitania/Carbon Composite Electrodes for Electrochemical Energy Storage

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