Abstract:The degradation of
methylene blue and rhodamine B dyes using potassium
hexatitanate nanoparticles (KTNPs) and potassium hexatitanate nanotubes
(KTNTs) synthesized via a hydrothermal method as efficient photocatalysts
under UV light irradiation was investigated. The kinetics of degradation
was determined for the two different catalysts––KTNPs
and KTNTs––by monitoring the optical absorption of the
dyes. The as-synthesized KTNPs were found to be spherical in shape
with an average particle size of ∼36 ± 1.7 nm, wh… Show more
“…Figure c presents the crystalline structures of the three types of TNTs, and the compositions of TNTs are mainly dominated by the synthesis process. Specifically, TiO 2 particles (anatase, rutile, or P25) are immersed in a high concentration of alkaline solution (NaOH or KOH) and then heated in facile conditions (generally <200 °C), and Na-TNTs (Na x H 2– x Ti 3 O 7 or Na 2 Ti 6 O 13 ) and K-TNTs (K 2 Ti 6 O 13 ) , can be fabricated (eqs –). Post-treatment using inorganic acid (HCl, HClO 4 , HNO 3 , H 2 SO 4 ) can further obtain H-TNTs (H 2 Ti 3 O 7 , eq ).…”
Section: Preparation Composition
and Properties Of Tntsmentioning
confidence: 99%
“…36-0654). K-TNTs is a hexatitanate with a chemical formula of K 2 Ti 6 O 13 (space group C 2/ m with monoclinic system a = 15.5 Å, b = 3.82 Å, c = 9.1 Å, β = 99.5°, JCPDS No. 40-0403).…”
Section: Preparation Composition
and Properties Of Tntsmentioning
confidence: 99%
“…The conventional TNTs can be classified into three types, i.e., sodium titanate (Na-TNTs), hydrogen titanate (H-TNTs), and potassium titanate (K-TNTs). Alkali-hydrothermal treatment is the most popular method for TNTs synthesis, ,,,− in which a TiO 2 precursor is heated in a high concentration of NaOH/KOH solution. The morphology, structure, and composition of TNTs can be well designed by controlling the synthesis conditions, such as the crystal phase of the TiO 2 precursor, , alkaline concentration, − reaction solvent, − hydrothermal temperature, ,− hydrothermal time, ,− washing acids, ,,− etc .…”
Photocatalysis
is an efficient technology for water decontamination
and purification. Development of photocatalysts with high activity
becomes the key to this research area. In recent years, titanate nanotubes
(TNTs), derived from TiO2 nanoparticles through hydrothermal
treatment with NaOH/KOH, have been attracting great attention. TNTs
are composed of edge-sharing [TiO6] octahedrons as the
skeleton and Na+/H+/K+ in the interlayers,
which exhibit a uniform tubular microstructure, a large specific surface
area, high photoelectric conversion properties, and good stability.
Therefore, TNTs and their modified materials are widely used for removal
of heavy metals and organic contaminants through photocatalytic oxidation
or reduction. In this perspective, we systematically summarize cutting-edge
research on the application of TNT-based photocatalysts in the water
treatment area, illustrate the challenges for fundamental research
and practical applications, and reveal the critical knowledge gaps
and research needs for the future. In particular, preparation and
specific properties of TNT-based photocatalysts are presented. Modification
of TNTs to promote photocatalytic activity is discussed as well as
their applications for contaminants removal from water. The latest
advances in theoretical calculations on materials and contaminants
in this photocatalysis system are clarified. In the future, strategic
programs on both fundamental research and practical applications of
TNT-based photocatalysts are proposed.
“…Figure c presents the crystalline structures of the three types of TNTs, and the compositions of TNTs are mainly dominated by the synthesis process. Specifically, TiO 2 particles (anatase, rutile, or P25) are immersed in a high concentration of alkaline solution (NaOH or KOH) and then heated in facile conditions (generally <200 °C), and Na-TNTs (Na x H 2– x Ti 3 O 7 or Na 2 Ti 6 O 13 ) and K-TNTs (K 2 Ti 6 O 13 ) , can be fabricated (eqs –). Post-treatment using inorganic acid (HCl, HClO 4 , HNO 3 , H 2 SO 4 ) can further obtain H-TNTs (H 2 Ti 3 O 7 , eq ).…”
Section: Preparation Composition
and Properties Of Tntsmentioning
confidence: 99%
“…36-0654). K-TNTs is a hexatitanate with a chemical formula of K 2 Ti 6 O 13 (space group C 2/ m with monoclinic system a = 15.5 Å, b = 3.82 Å, c = 9.1 Å, β = 99.5°, JCPDS No. 40-0403).…”
Section: Preparation Composition
and Properties Of Tntsmentioning
confidence: 99%
“…The conventional TNTs can be classified into three types, i.e., sodium titanate (Na-TNTs), hydrogen titanate (H-TNTs), and potassium titanate (K-TNTs). Alkali-hydrothermal treatment is the most popular method for TNTs synthesis, ,,,− in which a TiO 2 precursor is heated in a high concentration of NaOH/KOH solution. The morphology, structure, and composition of TNTs can be well designed by controlling the synthesis conditions, such as the crystal phase of the TiO 2 precursor, , alkaline concentration, − reaction solvent, − hydrothermal temperature, ,− hydrothermal time, ,− washing acids, ,,− etc .…”
Photocatalysis
is an efficient technology for water decontamination
and purification. Development of photocatalysts with high activity
becomes the key to this research area. In recent years, titanate nanotubes
(TNTs), derived from TiO2 nanoparticles through hydrothermal
treatment with NaOH/KOH, have been attracting great attention. TNTs
are composed of edge-sharing [TiO6] octahedrons as the
skeleton and Na+/H+/K+ in the interlayers,
which exhibit a uniform tubular microstructure, a large specific surface
area, high photoelectric conversion properties, and good stability.
Therefore, TNTs and their modified materials are widely used for removal
of heavy metals and organic contaminants through photocatalytic oxidation
or reduction. In this perspective, we systematically summarize cutting-edge
research on the application of TNT-based photocatalysts in the water
treatment area, illustrate the challenges for fundamental research
and practical applications, and reveal the critical knowledge gaps
and research needs for the future. In particular, preparation and
specific properties of TNT-based photocatalysts are presented. Modification
of TNTs to promote photocatalytic activity is discussed as well as
their applications for contaminants removal from water. The latest
advances in theoretical calculations on materials and contaminants
in this photocatalysis system are clarified. In the future, strategic
programs on both fundamental research and practical applications of
TNT-based photocatalysts are proposed.
“…[21][22][23] Herein, inspired by spider silk, we demonstrated polymer-based PDRC materials with significantly enhanced mechanical and photostabilities, through potassium titanate (K 2 Ti 6 O 13 ) nanofibers doped nanocomposite structure (Figure 1e). [24,25] To effectively enhance the mechanical properties and UV stabilities without affecting the optical properties of PDRC polymers, the option of dopant is critical. There are unique advantages of doping K 2 Ti 6 O 13 (PT) nanofibers in PDRC polymers.…”
of PVDF films. Furthermore, such nanocomposite film maintains a high reflectivity (96.5%) in the solar band and high emissivity (95.1%) in the atmospheric windows (Figure S15, Supporting Information), promising for excellent radiative cooling performance (Figure 5e,f).
ConclusionsWe have demonstrated a spider-silk-inspired nanocomposite strategy for building polymer-based PDRC materials with enhanced mechanical properties and UV durability. As a demonstration with PEO PDRC, by introducing potassium titanate nanofibers, its Young's modulus and UV resistance were increased by 7 and 12 times, respectively. As a result, the cooling performance of PT@PEO does not show any decline for over 720 h under natural sunshine. Additionally, such a nanocomposite method presents a universal reinforcing effect in various matrix materials. Therefore, our work provides a new pathway to fundamentally improve both the mechanical and the UV stability of polymer-based PDRC materials toward practical applications.
“…nanotubes, nanowires, nanorods, whiskers, etc) has led to the use of alkali hexatitanates as reinforcements and friction materials [4][5][6], among other applications. While studies on the structural, microstructural, electronic, optical, and electrical properties of A 2 Ti 6 O 13 are quite extensive in experiment [7][8][9][10][11][12][13][14][15], there are also other theoretical works on this topic to be found in the literature [4,[16][17][18][19]. However, the investigation into the mechanical/elastic properties have been limited [4,20].…”
The elastic properties of the alkali hexatitanate family A2Ti6O13 (A = H, Li, Na, K, and Rb) are investigated which based on Density Functional Theory (DFT) within Generalized Gradient Approximation plus Hubbard U (GGA+U) approach. The results showed that all members of the family are wide-band semiconductors and the calculated lattice parameters are consistent with experimental values. In terms of mechanical stability, the results indicated that the alkali hexatitanates are highly incompressible to uniaxial stress, with the largest elastic constant C22 reaching values as high as 265 GPa in K2Ti6O13. The obtained elastic constants, using the stress-strain method, were used to calculate bulk modulus, shear modulus, Young's modulus, brittleness and ductility, elastic anisotropy, Vickers hardness, sound velocities, and the Debye temperature. It was found that the member of the family with the highest atomic number of the alkaline group, Rb2Ti6O13, had the highest values of bulk, shear, and Young's modulus, as well as the lowest values of shear and compression anisotropy, and a high Vickers hardness.
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