Interlayer chemistry between thick transition-metal oxide layers: synthesis and intercalation reactions of K[Ca2Nan-3NbnO3n+1] (3 .ltoreq. n .ltoreq. 7)

Jacobson, Allan J.; Johnson, Jack W.; Lewandowski, J. T.

doi:10.1021/ic00217a006

Cited by 312 publications

(217 citation statements)

References 0 publications

Supporting

Mentioning

210

Contrasting

Order By: Relevance

“…The XRD patterns of KCa2Nb3O10 and HCa2Nb3O10 dried at 383 K were in good agreement with those reported in the literature [1][2][3]. Although the wet HCa2Nb3O10 contained 1.5 molecules of 1120, conversion to the anhydrate at 363 K was confirmed by the TG-DTA measurements.…”

Section: Resultssupporting

confidence: 89%

Ion-Exchange Reaction of n-Pentylamine-Intercalated Layered Perovskite with Alkali and Alkaline Earth Metal Ions in Aqueous Solution

Murakami

Imagawa

Sumiyoshi

et al. 2003

Journal of Ion Exchange

View full text Add to dashboard Cite

show abstract

Section: Resultssupporting

confidence: 89%

Ion-Exchange Reaction of n-Pentylamine-Intercalated Layered Perovskite with Alkali and Alkaline Earth Metal Ions in Aqueous Solution

Murakami

Imagawa

Sumiyoshi

et al. 2003

Journal of Ion Exchange

View full text Add to dashboard Cite

show abstract

“…The (100) lattice planes for the Ca 2 Nb 3 O 10 nanosheet of tetragonal symmetry are visible (0.368 nm) and in good agreement with the crystallographic data for the parent compound 0.387 ( 0.001 nm. 32 X-ray powder diffraction patterns of the covalently modified Ca 2 Nb 3 O 10 sheets and of the magnetite-nanosheet clusters are shown in Figure 5. The sharp reflections in part A belong to intra-sheet reflections of the exfoliated sheets, 33 while reflections from planes with indices (00l) are either broad or not observed because the periodicity in the c direction is lost after exfoliation of the sheets from the solid.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Real-Time Magnetic Manipulation of a Biaxial Superparamagnetic Colloid

et al. 2005

View full text Add to dashboard Cite

Superparamagnetic colloidal plates were synthesized from tetrabutylammonium stabilized Ca 2 Nb 3 O 10 nanosheets and oleic acid-stabilized Fe 3 O 4 nanoparticles. Modification with 3-aminopropyltrimethoxysilane produces amine-terminated Ca 2 Nb 3 O 10 with an amine concentration of 0.43 ( 0.06 groups per Ca 2 Nb 3 O 10 unit as follows from spectroscopic quantification with trinitrobenzenesulfonic acid as a dye. Treatment of the modified sheets in THF/ethanol with 5.3 nm oleic acid-stabilized magnetite nanoparticles yields pseudo-2D assemblies that consist of 2 nm thick nanosheets decorated on both sides with a dense collection (9.3 ( 0.5 × 10 3 particles per square micrometer per side) of magnetite particles. In noncoordinating or weakly coordinating solvents, these composite particles further aggregate into stacked aggregates with a mean edge length of 1.6 ( 0.7 µm and a thickness of 79 ( 30 nm. The colloidal plates were characterized by elemental analysis, X-ray powder diffraction, and infrared and UV/vis spectroscopy. SQUID measurements show that films of the aligned particles are superparamagnetic at room temperature. The magnetic hysteresis that is observed at 5 K reveals that the plates have a magnetic anisotropy with the easy axis in the plane of the plates and the hard axis perpendicular to it. Calculations show that the magnetic anisotropy is a direct consequence of the two-dimensional distribution of the magnetic nanoparticles on the sheets. Optical microscopy reveals that when suspended in ethanol or THF, the colloidal plates can be rotated in real time with a variable external magnetic field (200 Oe). Magnetic alignment of the particles in suspensions also produces asymmetric light scattering patterns and magnetic birefringence. These effects and the observed magneto-orientational properties make the biaxial colloids interesting as components in displays and as magnetic actuators.

show abstract

“…The thickness of the sheets was 1.16 nm, from crystallographic data. 16 Acidification of a nanosheet dispersion with dilute hydrochloric acid caused the nanosheets to stack up and precipitate from solution (eq 1). Transmission electron microscopy ( Figure 1C) confirmed that this solid was comprised of irregularly stacked and folded nanosheets.…”

mentioning

confidence: 99%

Calcium Niobate Semiconductor Nanosheets as Catalysts for Photochemical Hydrogen Evolution from Water

et al. 2007

View full text Add to dashboard Cite

We have studied the photochemical water splitting activity of individually dispersed, semiconductor nanosheets derived from the Dion-Jacobsen phase HCa 2 Nb 3 O 10 by exfoliation with tetrabutylammonium hydroxide. The dimensions of the nanosheets are 0.001 × 1.2 × 1.2 µm 3 based on TEM measurements and crystallographic data, and their band gap is determined as 3.53 eV based on the absorption band edge at 350 nm. When an aqueous suspension of the nanosheets is irradiated with light from a Hg lamp, hydrogen is produced at rates of up to 2.28 µmol/h with a quantum efficiency (QE) of 0.22%. No oxygen is evolved. Derivatization of the nanosheets with Pt nanoparticles increases the hydrogen production rate to 78.37 µmol (QE ) 7.5%). Restacking of the nanosheets at low pH does not significantly affect the catalytic activity. Transient absorption measurements of the nanosheets reveal charge separation on a nanosecond time scale.Predicted increases in global energy consumption and climate change driven by fossil fuel emissions have sparked a renewed interest in carbon-neutral energy sources. A recent analysis has shown that the conversion of solar energy into hydrogen is one of the most promising renewable energy technologies. 1 Since the discovery of the first artificial photocatalytic water splitting system in 1971, 2,3 many inorganic materials have been identified as active catalysts for the photochemical reduction of water. [4][5][6][7][8] However, limited light absorption in the visible, chemical instability of the catalyst materials, and short lifetimes of the excited states leading to incomplete charge separation continue to be key problems that prevent commercial applications of these catalysts. Some of these issues can be overcome with nanomaterials, whose large surface-to-volume ratio and short chargetransport pathways facilitate efficient charge transfer to water. This is well illustrated with layered group 4/5 metal oxides (Ti, Nb, Ta), whose exceptional quantum efficiencies for water reduction (up to 20% for K 4 Nb 6 O 17 ) 9 are commonly attributed to the large internal surface area of the material and improved charge transfer. [10][11][12][13][14][15] For comparison, the best catalyst for overall water splitting, La-doped NaTaO 3 , has a quantum efficiency of 56%. 9 Here, we show for the first time that individually dispersed [H 1-x Ca 2 Nb 3 O 10 ] x-(x ) 0.15-0.20) nanosheets are able to split pure water under UV irradiation and evolve hydrogen, but no oxygen. We find that the photocatalytic activity of the nanosheets is strongly influenced by the solution pH and by the presence of Pt nanoparticles as cocatalysts. Transient absorption spectroscopy measurements provide information about the excited-state dynamics of the nanosheets.

show abstract

Interlayer chemistry between thick transition-metal oxide layers: synthesis and intercalation reactions of K[Ca2Nan-3NbnO3n+1] (3 .ltoreq. n .ltoreq. 7)

Cited by 312 publications

References 0 publications

Ion-Exchange Reaction of n-Pentylamine-Intercalated Layered Perovskite with Alkali and Alkaline Earth Metal Ions in Aqueous Solution

Ion-Exchange Reaction of n-Pentylamine-Intercalated Layered Perovskite with Alkali and Alkaline Earth Metal Ions in Aqueous Solution

Synthesis and Real-Time Magnetic Manipulation of a Biaxial Superparamagnetic Colloid

Calcium Niobate Semiconductor Nanosheets as Catalysts for Photochemical Hydrogen Evolution from Water

Contact Info

Product

Resources

About