Synthesis and characterisation of nanotubular titanates and titania

Weng, Luqian; Song, Shenhua; Hodgson, Simon; Baker, Adam; Yu, Jie

doi:10.1016/j.jeurceramsoc.2005.01.058

Cited by 104 publications

(70 citation statements)

References 20 publications

(24 reference statements)

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“…Similarly, single crystals of acid-modified Zr-Ti alkoxide were also synthesized in scCO 2 , as shown in Figure 6a. [22] The Zr-modified (Zr 2 Ti 4 (m 3 -O) 4 (OPr) 4 (m-OPr) 2 (m-OAc) 10 ) hexamer is quite different from the previously-observed titania hexamer. Figure 6b shows a typical unit cell containing four single units along the [100] plane in which the four end -OPr groups are situated on top, the other four groups on the bottom, and only two groups are present along the side.…”

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confidence: 99%

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A One‐Step Approach to the Synthesis of ZrO₂‐Modified TiO₂ Nanotubes in Supercritical Carbon Dioxide

Lucky

Charpentier

2008

Advanced Materials

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Recently, considerable effort has been devoted to synthesizing materials with one-dimensional (1D) nanostructures due to their unique properties and potential applications in a diversity of applications including catalysis, high-efficiency solar cells, coatings, and sensors.[1] Particularly, titania (TiO 2 ) nanotubes are receiving considerable attention due to titania's high activity, strong oxidation capability, and chemical stability. In addition, being a low-cost material, TiO 2 is favorable for potential large-scale commercial applications. The performance of titania nanomaterials strongly relies on their crystallinity, crystallite size, crystal structure, specific surface area, thermal stability and quantum efficiency. [2,3] These properties highly depend on both the synthesis method, and the subsequent thermal-treatment technique -calcination. In some cases, doping with a second metal has been found very effective to improve the properties of TiO 2 . Zirconia has been reported as one of the most suitable dopants to enhance the thermal stability and activity of TiO 2 nanomaterials. [4][5][6] Conventionally, anodization, [7] template techniques, [8,9] hydrothermal processes, [10,11] and soft chemical processes [12] have been used to prepare TiO 2 nanotubes. However, each of these methods has limitations. The template technique requires high calcination temperatures to remove the template, resulting in a collapse of the tubular structure in the product.[12]Anodizing processes produce nanotubes with relatively-large diameters.[13] The multistep hydrothermal process requires a large amount of inorganic solvents, which may lead to environmental pollution. Due to these limitations, alternative processes using a green solvent such as supercritical carbon dioxide (scCO 2 ) are attractive to synthesize TiO 2 nanotubes. Previously, our group developed a direct sol-gel process to synthesize TiO 2 nanofibers, [14] where scCO 2 was used in place of an organic solvent. There are several favorable properties that make CO 2 an attractive solvent for the synthesis and processing of high-quality porous materials. Firstly, CO 2 is inexpensive, environmentally benign and non-flammable, with mild critical conditions (P c ¼ 73.8 bar; T c ¼ 31.1 8C), which makes this a green solvent that is suitable for both laboratory and commercial scale application. Furthermore, its physical properties such as density and solubility can be tuned by adjusting the operating temperature and pressure. Low viscosity, zero surface tension and high diffusivity of scCO 2 are also favorable in synthesizing superior ultrafine and uniform nanomaterials. In addition, scCO 2 can be easily and completely removed from products by venting; hence, no drying process is required and the porous structure can be maintained without collapsing the nanostructure. In addition, scCO 2 can be easily recycled after the pressure is diminished for potential scale-up applications. While exploring the synthesis of ZrO 2 -modified TiO 2 nanostructures by sol-gel methods in sc...

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“…Zirconia has been reported as one of the most suitable dopants to enhance the thermal stability and activity of TiO 2 nanomaterials. [4][5][6] Conventionally, anodization, [7] template techniques, [8,9] hydrothermal processes, [10,11] and soft chemical processes [12] have been used to prepare TiO 2 nanotubes. However, each of these methods has limitations.…”

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confidence: 99%

A One‐Step Approach to the Synthesis of ZrO₂‐Modified TiO₂ Nanotubes in Supercritical Carbon Dioxide

Lucky

Charpentier

2008

Advanced Materials

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“…The synthesized TNTs have a hydrophilic surface, exchangeable cation sites on the surface, and a high surface area and pore volume (Lee et al, 2007). Moreover, the surface characteristics of TNTs might vary with the synthesis conditions, including the reaction time, synthesis temperature, acid concentration during washing, and calcination temperature (Weng et al, 2006;Lee et al, 2008). By exploiting its properties, several researchers have used TNTs to adsorb basic dyes or cations in aqueous systems (Yoshida et al, 2005;Lee et al, 2007Lee et al, , 2010.…”

Section: Introductionmentioning

confidence: 99%

Sorption of Volatile Organic Compounds on Organic Substance-Modified Titanate Nanotubes

Wang

Peng

Chao

2015

Aerosol Air Qual. Res.

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This study investigates the removal of volatile organic compounds (VOCs) from the air through the use of organic substance-modified titanate nanotubes (TNTs). The TNTs were derived from TiO 2 through a hydrothermal method, and were modified using hexadecyltrimethylammonium bromide and octadecyltrichlorosilane (OTS) to change the surface hydrophilicity to hydrophobicity. The properties of the TNT and modified TNT were characterized through scanning electron microscopy , transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle measurements, and nitrogen adsorption-desorption isotherms. The fabricated adsorbents were used to remove the VOCs of toluene, ethylbenzene 1,1,2-trichloroethane, and tetrachloroethene in the air. The adsorption amounts of the VOCs were estimated using the Thomas equation. The results revealed that adsorbent modification raised the adsorption capacities of these VOCs, which also grew with increasing surface hydrophobicity. The aromatic compounds accumulated easily in the pores to generate relatively high adsorption amounts. VOCs adsorbed on the TNT surface or partitioned into the organic substance on TNTs. The adsorption amounts of VOCs on the OTSmodified TNTs were higher than those on commercial activated carbon. The results imply that organic substance-modified TNTs can effectively remove VOCs in the air and become excellent adsorbents.

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“…In recent years, mesoporous molecular sieves, such as FSM-16 (Mohamed 2004), MCM-22 , and MCM-41 (Ho et al 2003) have been accepted as the appropriate adsorbents for the removal of dyes from wastewater due to their unique mesoporous pore structure, high specific surface area, and pore volume. In addition, titania nanotubes (TN) derived from a hydrothermal method, possesses ion-exchange characteristics (Kasuga et al 1999;Seo et al 2001;Ryuhei et al 2005;Kasuga 2006;Weng et al 2006;Yu et al 2006a;Zhang et al 2008;Niu et al 2009) and they may also offer a special environment for the adsorption of large cations, such as basic dyes. Titania nanotubes with high specific surface area has been also studied due to its excellent catalytic activities, long-term stability, non-toxicity, and low cost (Tomoko et al 1998;Chen et al 2002;Uzunova-Bujnova et al 2008;Inagaki et al 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Titania nanotubes with high specific surface area has been also studied due to its excellent catalytic activities, long-term stability, non-toxicity, and low cost (Tomoko et al 1998;Chen et al 2002;Uzunova-Bujnova et al 2008;Inagaki et al 2009). Many groups have tried to analyze the characteristics of TN, from which the synthetic mechanism was examined and the sheet folding mechanism was often assumed (Wang et al 2002;Weng et al 2006;Yu et al 2006b;Lee et al 2008;Hsieh et al 2009;Prado and Costa 2009;Zhao et al 2009). The effects of synthetic conditions on the microstructures of the TiO 2 -derived nanotubes with the emphasis placed on the reaction time, synthesis temperature, and acid washing concentration were also investigated (Tomoko et al 1998;Seo et al 2001;Wang et al 2002;Weng et al 2006;Lee et al 2008;Zhang et al 2008;Wu et al 2009;Yu et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization, and adsorption kinetics of titania nanotubes for basic dye wastewater treatment

et al. 2010

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Titanium dioxide has been recognized as an excellent photocatalyst material applied on many fields especially for environmental science or engineering. However, the effect of acid washing treatment on the morphology or phase and pore structures of titania nanotubes (TNs) has not still been clearly investigated. The variation of morphology, formation mechanism, phase structure, and pore structure of TN were thus characterized with FE-SEM, TEM, XRD, and N 2 BET isotherms, respectively in the present work. Titania nanotube synthesized via a simple hydrothermal chemical process formed a crystalline structure with open-ended and multiwall morphologies. The XRD patterns and N 2 BET isotherms implied that the acid washing techniques could improve the TN surface area and the pore size distribution up to 292 m 2 g −1 and 40-60 nm, respectively. According to EXAFS/XANES spectra, the structure of the TN is closer to the anatase specimen and much more correlated with octahedral structure. Effects of the pore structure variation on basic dye (Basic Green 5 (BG5)) adsorption by TN were discussed in the present work. Moreover, the adsorption ability, mechanisms, and kinetics of BG5 dye onto TN were also examined with the aid of model analyses of the adsorption equilibrium and kinetic data. Therefore, the potential of TN for the removal of BG5 dye contaminant from wastewaters implied that further development would be warranted.

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Synthesis and characterisation of nanotubular titanates and titania

Cited by 104 publications

References 20 publications

A One‐Step Approach to the Synthesis of ZrO₂‐Modified TiO₂ Nanotubes in Supercritical Carbon Dioxide

A One‐Step Approach to the Synthesis of ZrO₂‐Modified TiO₂ Nanotubes in Supercritical Carbon Dioxide

Sorption of Volatile Organic Compounds on Organic Substance-Modified Titanate Nanotubes

Synthesis, characterization, and adsorption kinetics of titania nanotubes for basic dye wastewater treatment

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Synthesis and characterisation of nanotubular titanates and titania

Cited by 104 publications

References 20 publications

A One‐Step Approach to the Synthesis of ZrO2‐Modified TiO2 Nanotubes in Supercritical Carbon Dioxide

A One‐Step Approach to the Synthesis of ZrO2‐Modified TiO2 Nanotubes in Supercritical Carbon Dioxide

Sorption of Volatile Organic Compounds on Organic Substance-Modified Titanate Nanotubes

Synthesis, characterization, and adsorption kinetics of titania nanotubes for basic dye wastewater treatment

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A One‐Step Approach to the Synthesis of ZrO₂‐Modified TiO₂ Nanotubes in Supercritical Carbon Dioxide

A One‐Step Approach to the Synthesis of ZrO₂‐Modified TiO₂ Nanotubes in Supercritical Carbon Dioxide