The effects of (Na+K)/Na molar ratio and kinetic studies on the rapid crystallization of a large pored titanium silicate, ETS-10 using cost efficient titanium oxysulfate, TiOSO4 under stirring

Noh, Si Hyun; Kim, Shin Dong; Chung, Yun Joon; Park, Jun Woo; Moon, Doo Kyung; Hayhurst, David T.; Kim, Wha Jung

doi:10.1016/j.micromeso.2005.09.014

Cited by 20 publications

(9 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…None of the reported synthetic methods have adopted this methodology. [12][13][14][15][20][21][22][23][24][25] Another important discovery is that the average size of the ETS-10 crystals was inversely proportional to the amount of anatase nanoparticles produced in the solution ( Figure SI-3).…”

mentioning

confidence: 99%

Length‐Dependent Band‐Gap Shift of TiO₃²⁻ Molecular Wires Embedded in Zeolite ETS‐10

Jeong¹,

Lee²,

Yoon³

2007

Angew Chem Int Ed

View full text Add to dashboard Cite

Efforts have been directed at the synthesis and characterization of 1D quantum-confined semiconductor materials, since they have great potential to be widely used as building blocks for nanoscale electronic devices and other novel applications. [1][2][3][4][5][6][7][8][9][10][11] Of the 1D quantum-confined semiconductor materials, molecular wires are the thinnest. [1][2][3][4][5] However, examples of molecular wires are still very rare, and there is no method of synthesizing them in uniform diameters and controlled lengths. Accordingly, the relationship between the wire length (l) and the band-gap energy (E g ) in the quantum confinement region has not yet been determined for molecular wires, despite the fact that this relationship is crucial for the elucidation of the properties of the wires.Zeolites are crystalline inorganic materials having nanometer-sized pores and channels with uniform shapes and sizes. These materials are widely used as catalysts, catalyst supports, adsorbents, ion-exchangers, and molecular sieves. ETS-10 (Na 2 TiSi 5 O 13 ) is a unique titanosilicate zeolite that contains regularly spaced 1D TiO [12-15] Each TiO 3 2À wire is surrounded by nanoporous silica with a pore size of 8 5 2 . In highly crystalline ETS-10, the lengths of the TiO 3 2À molecular wires are greater than 25 nm. [16,17] Hence, it would be difficult to determine the l-E g relationship in the quantum confinement region unless the Bohr radius of the exciton in the molecular wire were to exceed 25 nm, since the quantum confinement effect (E g increases with decreasing l) is observed only in the region in which l is smaller than the exciton Bohr radius.The diameter of the TiO 3 2À molecular wire in ETS-10 is comparable to that of a single-wall carbon nanotube (d = 0.7 nm).[2] However, from the point of view of titanates, an important class of inorganic materials widely used in industry, the TiO 3 2À molecular wire is ultimately the thinnest wire. Furthermore, no other molecular wires or nanorods have been produced in the form of a superlattice embedded in a chemically inert large-band-gap medium. ETS-10 can be produced in large quantities at low cost by hydrothermal synthesis.[12-15] Therefore, ETS-10 provides an unprecedented opportunity to systematically study the l-E g relationship of the titanate molecular wire and to explore the applications of molecular-wire superlattices as advanced materials.Zecchina and co-workers, however, assumed that the band gap of the TiO 3 2À wire in ETS-10 is independent of the length of the wire when the length is greater than 25 nm. [16,17] This assumption has been widely accepted by the community during the last decade. [18,19] The verification of its validity has not been possible owing to the inability to synthesize highquality ETS-10 crystals of different sizes.[20] The standard approach to vary the size of a zeolite crystal is to vary the reaction time and temperature. Unfortunately, this standard approach has not worked for ETS-10. For instance, Southon and Howe demonstrated that, for a...

show abstract

mentioning

confidence: 99%

Length‐Dependent Band‐Gap Shift of TiO₃²⁻ Molecular Wires Embedded in Zeolite ETS‐10

Jeong¹,

Lee²,

Yoon³

2007

Angew Chem Int Ed

View full text Add to dashboard Cite

show abstract

“…However, ETS-10 synthesis is very difficult because the crystallization region of ETS-10 is limited to a narrow composition and pH zone. Noh et al [3] studied the effects of the (Na+K)/Na molar ratio on ETS-10 crystallization and phase purity. They reported at (Na+K)/Na molar ratio lower than 1.26 pure ETS-10 is hardly formed.…”

Section: Introductionmentioning

confidence: 99%

“…Among the varieties of Engelhard titanosilicates, ETS-4 and ETS-10 received the most attention. ETS-4 is a small pored sieve with a 3.7 Å pore opening and ETS-10 is a large pored sieve with a pore opening of 8 Å. ETS-10 exhibits much better thermal stability than ETS-4 and has potential catalytic, adsorptive, and ionexchange properties [3,4]. In ETS-10, the SiO 4 and TiO 6 are forming a threedimensional 12-membered ring network [5].…”

Section: Introductionmentioning

confidence: 99%

Synthesis pure ETS-10 by optimization synthesis parameters using One Factor At a Time (OFAT) approach: CO 2 adsorption study

Khademi

Babakhani²,

Towfighi

et al. 2023

Preprint

View full text Add to dashboard Cite

In this work, ETS-10 was synthesized by hydrothermal method. The effect of synthesis parameters of ETS-10 on purity and characterization was studied by One At a Time (OFAT) approach. According to this approach, in each test, one synthesis parameter was changed while the other parameters were kept constant. All samples were identified by PXRD and the purest sample was characterized by SEM, EDX, BET, and TGA/DTA. To evaluate the CO2 capture abilities of the synthesized purest sample, CO2 adsorption isotherm at 298 K was obtained by the constant-volume adsorption method. The isotherm models Dual-site Langmuir, Toth, and UNILAN were used to fit the obtained isotherm data. The results showed that with gel pH = 11.3, crystallization temperature 230°C, and crystallization time 72 h, the ETS-10 with the highest purity was achieved. Also, it was observed that there is an important interaction between the potassium source with other synthesis parameters. The adsorption results showed that the CO2 adsorption capacity of the pure ETS-10 was 3.37 mmol/g. It was observed that the Dual-site Langmuir model was fitted better the CO2 adsorption data at 298 K compared to Toth and UNILAN models. The adsorption kinetics showed that about 90% of the equilibrium adsorption was reached within 25s which demonstrates a remarkable fast kinetics.

show abstract

“…In addition to these important contributions, it has been reported that the molar ratio of Na/K in the initial synthesis gel can affect the crystallization kinetics and morphology of ETS‐10 22. 23 By decreasing the concentration of alkali‐metal cations or by adjusting the type of alkali‐metal cations, the length of the crystalline axis can be increased or decreased in two or three directions 23. Although the effect of Na + and K + ions during the crystallization of zeolites is very complex and far from well understood, it provides a method for tuning the exposed active sites for AM‐6 on the basis of morphology control.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Morphology Control of AM‐6 Nanofibers with Tailored ‐V‐O‐V‐ Intermediates

Guo

Feng

Hofmann

et al. 2013

Chemistry A European J

View full text Add to dashboard Cite

Microporous vanadosilicates with octahedral VO6 and tetrahedral SiO4 units, better known as AM-6, have been hydrothermally synthesized with different morphologies by controlling the Na/K molar ratio of the initial gel mixtures. The morphology of the AM-6 materials changed from bulky cube to nanofiber aggregates as the Na/K molar ratio decreased from 1.9 to 0.2. Raman spectroscopy revealed that the VO3 (-) intermediate species plays an important role in the formation of the nanofiber morphology. The orientation of -V-O-V- chains in nanofiber aggregates was examined by confocal polarized micro-Raman spectroscopy. It was found that these aggregates are assemblies of short -V-O-V- chains perpendicular to the axis of nanofibers. The obtained AM-6 nanofibers greatly increase the exposed proportion of VO terminals, and thus improve the catalytic performance.

show abstract

The effects of (Na+K)/Na molar ratio and kinetic studies on the rapid crystallization of a large pored titanium silicate, ETS-10 using cost efficient titanium oxysulfate, TiOSO4 under stirring

Cited by 20 publications

References 15 publications

Length‐Dependent Band‐Gap Shift of TiO₃²⁻ Molecular Wires Embedded in Zeolite ETS‐10

Length‐Dependent Band‐Gap Shift of TiO₃²⁻ Molecular Wires Embedded in Zeolite ETS‐10

Synthesis pure ETS-10 by optimization synthesis parameters using One Factor At a Time (OFAT) approach: CO 2 adsorption study

Synthesis and Morphology Control of AM‐6 Nanofibers with Tailored ‐V‐O‐V‐ Intermediates

Contact Info

Product

Resources

About

The effects of (Na+K)/Na molar ratio and kinetic studies on the rapid crystallization of a large pored titanium silicate, ETS-10 using cost efficient titanium oxysulfate, TiOSO4 under stirring

Cited by 20 publications

References 15 publications

Length‐Dependent Band‐Gap Shift of TiO32− Molecular Wires Embedded in Zeolite ETS‐10

Length‐Dependent Band‐Gap Shift of TiO32− Molecular Wires Embedded in Zeolite ETS‐10

Synthesis pure ETS-10 by optimization synthesis parameters using One Factor At a Time (OFAT) approach: CO 2 adsorption study

Synthesis and Morphology Control of AM‐6 Nanofibers with Tailored ‐V‐O‐V‐ Intermediates

Contact Info

Product

Resources

About

Length‐Dependent Band‐Gap Shift of TiO₃²⁻ Molecular Wires Embedded in Zeolite ETS‐10

Length‐Dependent Band‐Gap Shift of TiO₃²⁻ Molecular Wires Embedded in Zeolite ETS‐10