The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Chemistry and properties of nanocrystals of different shapes.

https://pure.mpg.de/pubman/item/item_2225903_3/component/file_2261322/2225903.pdf

Calcium phosphates in biomedical applications: materials for the future?

Proton conducting alkaline earth zirconates and titanates for high drain electrochemical applications

Diffuse phase transition and dielectric tunability of Ba(ZryTi1−y)O3 relaxor ferroelectric ceramics

Reactors based on particle suspensions for the capture, conversion, storage, and use of solar energy as H2 are projected to be cost-competitive with fossil fuels. In light of this, this review paper summarizes state-of-the-art particle light absorbers and cocatalysts as suspensions (photocatalysts) that demonstrate visible-light-driven water splitting on the laboratory scale. Also presented are reactor descriptions, theoretical considerations particular to particle suspension reactors, and efficiency and performance characterization metrics. Opportunities for targeted research, analysis, and development of reactor designs are highlighted.

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Particle suspension reactors and materials for solar-driven water splitting

Sol-gel synthesis of nano-sized BaTiO3, BaZrO3 and BaTi05Zr05O3 ceramics using alkoxide and semi-alkoxide routes has been investigated and the pervoskites obtained have been compared with respect to crystallisation temperature, crystallite size and compositional purity Heterometal alkoxides containing two (for BaTiO3 and BaZrO3) and three (for BaTi05Zr05O3) different metals were used as single-source precursors in the alkoxide route while semi-alkoxide synthesis was performed by reacting barium hydroxide or acetate with Ti and/or Zr alkoxides Semi-alkoxide synthesis also produces stoichiometric and phase-pure oxides, however, at temperatures higher than 1000°C At temperatures below 1000°C, BaCO3 and small amounts of other undesired phases (eg, BaTi2O4) were present in the oxides derived from semi-alkoxide synthesis Thermal behaviour, studied by TGA/DTA measurements, shows that thermal decomposition occurs in three major steps and depends on the educt composition and the synthesis route Among alkoxide derived powders, crystalline BaTi05Zr05O3 phase is formed at 400°C while complete crystallisation of BaMO3 ceramics occurs around 600°C The cubic to tetragonal phase transition for BaTiO3 is clearly observed at relatively low-temperature of 800°C The stoichiometry and phase homogeneity of the obtained powders were demonstrated by energy dispersive X-ray analysis and powder diffractometry The averaged crystallite size of the obtained nano-ceramics was evaluated using the FormFit programme SEM and TEM observations revealed a high microstructural uniformity

Sol-Gel Synthesis of Nano-Scaled BaTiO3, BaZrO3 and BaTi0.5Zr0.5O3 Oxides via Single-Source Alkoxide Precursors and Semi-Alkoxide Routes

Nanometer-sized zinc aluminate (ZnAl2O4) particles were synthesized from heterometal alkoxides, [ZnAl2(OR)8], possessing an ideal cation stoichiometry for the ZnAl2O4 spinel. ZnAl2O4 is formed at 400°C, which is the lowest temperature reported for the formation of monophasic ZnAl2O4. 27Al magic-angle spinning nuclear magnetic resonance spectroscopy revealed that ZnAl2O4 possesses an inverse structure at <900°C, while the normal spinel phase is observed at higher temperatures. The homogeneity of the in-depth composition and Zn:Al stoichiometry (1:2) was confirmed by electron spectroscopy for chemical analysis. Evaluation of the valence-band spectra of ZnAl2O4 and ZnS suggested that the hybridization of O 2p and Zn 3d orbitals is responsible for lowering the bandgap in the latter. The average crystallite size showed an exponential relationship to the calcination temperature (X-ray diffractometry and transmission electron microscopy data). The optical spectra of different spinel powders (average particle sizes, 20–250 nm) showed that the absorption edge exhibits a blue shift as particle size decreases.

Single-Source Sol-Gel Synthesis of Nanocrystalline ZnAl2O4: Structural and Optical Properties

Synthesis and characterization of the La1−xSrxFeO3−δ system and the fluorinated phases La1−xSrxFeO3−xFx

Synthesis and characterisation of the SrxBa1−xFeO3−y-system and the fluorinated phases SrxBa1−xFeO2F

Nanosized powders of SrTiO3 have been prepared via combustion synthesis. Aqueous solutions of the metal nitrates and differing amounts of EDTE as reducing and NH4NO3 as oxidizing reactant were evaporated and the resulting solid mixtures were ignited at different temperatures. As determined form XRD, the products exhibit crystallite sizes up to 42 nm with high microstress values resulting from the short reaction time. Crystallite size distributions were mostly very broad and could not be described by a single log-normal function, these results were confirmed by TEM images. The properties of the products could be explained as depending on the composition of the educt mixtures and the ignition temperatures.

Robert Haberkorn

Papers

Sol-Gel Synthesis of Nano-Scaled BaTiO3, BaZrO3 and BaTi0.5Zr0.5O3 Oxides via Single-Source Alkoxide Precursors and Semi-Alkoxide Routes

Single-Source Sol-Gel Synthesis of Nanocrystalline ZnAl2O4: Structural and Optical Properties

Synthesis and characterization of the La1−xSrxFeO3−δ system and the fluorinated phases La1−xSrxFeO3−xFx

Synthesis and characterisation of the SrxBa1−xFeO3−y-system and the fluorinated phases SrxBa1−xFeO2F

Combustion-synthesis of SrTiO3 Part I. synthesis and properties of the ignition products