Search

In recent years, the fabrication of functional nanostructures with multicomponents for a variety of novel biosensors has received considerable attention due to their synergistic improved sensitivity. Herein, we report a facile approach for the preparation of Fe 3 O 4 /nitrogen-doped carbon (Fe 3 O 4 /N-C) hybrid nanofibers, and construct a sensing platform for the sensitive colorimetric detection of H 2 O 2 and ascorbic acid (AA). During the synthetic process, a discontinuous layer of polypyrrole (PPy) is first polymerized in situ on the surface of the α-Fe 2 O 3 nanofibers under hydrothermal reaction using α-Fe 2 O 3 nanofibers as both a template and an oxidant. Then the prepared α-Fe 2 O 3 /PPy nanofibers are converted into Fe 3 O 4 /N-C hybrid nanofibers through pyrolysis with a thermochemical reduction process. The resulting Fe 3 O 4 /N-C hybrid nanofibers are used as a novel peroxidase mimic towards the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H 2 O 2 , with a superior catalytic activity over individual α-Fe 2 O 3 nanofibers, α-Fe 2 O 3 /PPy nanofibers, Fe 3 O 4 /C nanofibers, and commercial Fe 3 O 4 nanoparticles. Based on the high peroxidase-like activity of Fe 3 O 4 /N-C hybrid nanofibers, a sensing platform for the colorimetric detection of AA is developed. A good linear relationship from 0 to 50 μM and a detection limit of 0.04 μM are achieved. This work offers a new method for the preparation of Fe 3 O 4 /N-C hybrid nanofibers and presents new potential applications in biosensing, medical diagnostics and environmental monitoring.

Transition-metal phosphides (TMPs) have recently emerged as efficient and inexpensive electrocatalysts for electrochemical water splitting. The synthesis of nanostructured phosphides often involves highly reactive and hazardous phosphorous-containing compounds. Herein, we report the synthesis of nickel phosphides through thermal treatment under H 2 (5%)/Ar of layered nickel phenylphosphonate (NiPh) or methylphosphonate (NiMe) that act as single-source precursors. Ni 12 P 5 , Ni 12 P 5 -Ni 2 P, and Ni 2 P nanoparticles (NPs) with sizes of ca. 15-45 nm coated with a thin shell of carbonaceous material were produced. Thermogravimetric analysis coupled with mass spectrometry (TG-MS) showed that H 2 , H 2 O, P 2 , and -C 6 H 5 are the main compounds formed during the transformation of the precursor under argon and no hazard phosphorous-containing compounds are created, making this a simple and relatively safe route for fabricating nanostructured TMPs. The H 2 most likely reacts with the -PO 3 groups of the precursor to form H 2 O and P 2 , and the latter subsequently reacts with the metal to produce the phosphide. The Ni 12 P 5 -Ni 2 P and Ni 2 P NPs efficiently catalyze the hydrogen evolution reaction (HER), with Ni 2 P showing the best performance and generating a current density of 10 mA cm -2 at an overpotential of 87 mV and exhibiting long-term stability. Co 2 P and CoP NPs were also synthesized following this method. This approach may be utilized to explore the rich metal phosphonate chemistry for fabricating phosphide-based materials for electrochemical energy conversion and storage applications.

Aim: Tunable size ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles from 3 to 9 nm coated with polyethylene glycol phosphonate moieties have been designed for neovascularization MRI., Materials & Methods: USPIO were synthesized using a nonaqueous sol-gel method. An ischemia-reperfusion rat model has been chosen for neo-angiogenesis and scanned on MRI after injection of different sized USPIO. Histological studies have been performed for USPIO localization within the tissue., Results: The magnetic properties and consequently their MRI relaxivities are drastically dependent on the crystalline core size. In vivo MRI spots were observed specifically in the ischemic area. The best MRI contrast within neovascularization is generated by 6 nm nanoparticles proving that compromise between T 2 relaxivity and physico-chemical properties is essential for the design of effective MRI contrast agent.

The practical implementation of Li-S technology has been hindered by short cycle life and poor rate capability owing to deleterious effects resulting from the varied solubilities of different Li polysulfide redox products. Here, we report the preparation and utilization of composites with a sulfur-rich matrix and molybdenum disulfide (MoS2) particulate inclusions as Li-S cathode materials with the capability to mitigate the dissolution of the Li polysulfide redox products via the MoS2 inclusions acting as "polysulfide anchors". In situ composite formation was completed via a facile, one-pot method with commercially available starting materials. The composites were afforded by first dispersing MoS2 directly in liquid elemental sulfur (S8) with sequential polymerization of the sulfur phase via thermal ring opening polymerization or copolymerization via inverse vulcanization. For the practical utility of this system to be highlighted, it was demonstrated that the composite formation methodology was amenable to larger scale processes with composites easily prepared in 100 g batches. Cathodes fabricated with the high sulfur content composites as the active material afforded Li-S cells that exhibited extended cycle lifetimes of up to 1000 cycles with low capacity decay (0.07% per cycle) and demonstrated exceptional rate capability with the delivery of reversible capacity up to 500 mAh/g at 5 C.

A stable and durable electrochemical water oxidation catalyst based on CoO functionalized ZnO nanorods (NRs) is introduced. ZnO NRs were grown on fluorine-doped tin oxide (FTO) by using a low-temperature chemical solution method and were functionalized with cobalt oxide by electrochemical deposition. The electrochemical water oxidation performance of cobalt oxide functionalized ZnO NRs was studied under alkaline (pH = 10) conditions. From these studies, it is noticed that cobalt oxide functionalized ZnO NRs show electrocatalytic activity toward water oxidation with current density on the order of several mA cm(-2). Further, 30 s CoO deposited ZnO nanorods exhibited excellent galvanostatic stability at a current density of 1 mA cm(-2) and potentiostatic stability at 1.25 V vs Ag/AgCl over an electrolysis period of 1 h.

Sensor technology has an important effect on many aspects in our society, and has gained much progress, propelled by the development of nanoscience and nanotechnology. Current research efforts are directed toward developing high-performance gas sensors with low operating temperature at low fabrication costs. A gas sensor working at room temperature is very appealing as it provides very low power consumption and does not require a heater for high-temperature operation, and hence simplifies the fabrication of sensor devices and reduces the operating cost. Nanostructured materials are at the core of the development of any room-temperature sensing platform. The most important advances with regard to fundamental research, sensing mechanisms, and application of nanostructured materials for room-temperature conductometric sensor devices are reviewed here. Particular emphasis is given to the relation between the nanostructure and sensor properties in an attempt to address structure-property correlations. Finally, some future research perspectives and new challenges that the field of room-temperature sensors will have to address are also discussed., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Nearly 80% of all the nano-powders produced worldwide are metal oxides, and among these materials titanium dioxide (TiO2 ) is one of the most produced. Titanium dioxide's toxicity is estimated as low to soil organisms, but some studies have shown that TiO2 nanoparticles can cause oxidative stress. Additionally, it is known that TiO2 is activated by ultraviolet (UV) radiation, which can promote photocatalytic generation of reactive oxygen species, which is seldom taken into account in toxicity testing. In the present study, the authors investigated the effects of different TiO2 and zirconium materials on the soil oligochaete Enchytraeus crypticus, using exposure via soil, water, and soil:water extracts, and studied the effects combined with UV radiation. The results showed that zirconium dioxide (bulk and nano) was not toxic, whereas zirconium tetrachloride reduced enchytraeid reproduction in soil (50% effect concentration = 502 mg/kg). The TiO2 materials were also not toxic via soil exposure or under UV radiation. However, pre-exposure to TiO2 and UV radiation via aqueous media caused a lower reproductive output post-exposure in clean soil (20-50% less but only observed at the lowest concentration tested, 1 mg/L); that is, the effect of TiO2 in water was potentiated by the UV radiation and measurable as a decrease in reproduction in soil media., (© 2015 SETAC.)

This contribution provides a comprehensive mechanistic picture of the gold nanoparticle synthesis by citrate reduction of HAuCl4, known as Turkevich method, by addressing five key questions. The synthesis leads to monodisperse final particles as a result of a seed-mediated growth mechanism. In the initial phase of the synthesis, seed particles are formed onto which the residual gold is distributed during the course of reaction. It is shown that this mechanism is a fortunate coincidence created by a favorable interplay of several chemical and physicochemical processes which initiate but also terminate the formation of seed particles and prevent the formation of further particles at later stages of reaction. Since no further particles are formed after seed particle formation, the number of seeds defines the final total particle number and therefore the final size. The gained understanding allows illustrating the influence of reaction conditions on the growth process and thus the final size distribution.

Amorphous titanium dioxide-coated carbon nanotubes (CNTs) were prepared by atomic layer deposition (ALD) and investigated as sensing layers for resistive NO2 and O2 gas sensors. By varying ALD process conditions and CNT structure, heterostructures with different metal oxide grain size, morphology and coating thickness were synthesized. Higher responses were observed with homogeneous and continuous 5.5 nm thick films onto CNTs at an operating temperature of 150 °C, while CNTs decorated with either discontinuous film or TiO2 nanoparticles showed a weak response close to the one of device made of bare CNTs. An unexpected p-type behavior in presence of the target gas was also noticed, independently of the metal oxide morphology and thickness. Based on previous works, hypotheses were made in order to explain the p-type behavior of TiO2/CNT sensors.

The surface of long TiO2 nanotube (NT) electrodes in dye-sensitized solar cells (DSSCs) was modified without post-annealing by using atomic layer deposition (ALD) for the enhancement of photovoltage. Vertically oriented TiO2 NT electrodes with highly ordered and crack-free surface structures over large areas were prepared by a two-step anodization method. The prepared TiO2 NTs had a pore size of 80 nm, and a length of 23 μm. Onto these TiO2 NTs, an Al2O3 shell of a precisely controlled thickness was deposited by ALD. The conformally coated shell layer was confirmed by high-resolution transmission electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The open-circuit voltage (V(oc)) of the DSSCs was gradually enhanced as the thickness of the Al2O3 shell of the TiO2/Al2O3 NT electrodes was increased, which resulted from the enhanced electron lifetime. The enhanced electron lifetime caused by the energy barrier effect of the shell layer was measured quantitatively by the open-circuit voltage decay technique. As a result, 1- and 2-cycle-coated samples showed enhanced conversion efficiencies compared to the bare sample.

White light-emitting diodes (WLEDs) are candidates to revolutionize the lighting industry towards energy efficient and environmental friendly lighting and displays. The current challenges in WLEDs encompass high luminous efficiency, chromatic stability, high colour-rending index and price competitiveness. Recently, the development of efficient and low-cost downconverting photoluminescent phosphors for ultraviolet/blue to white light conversion was highly investigated. Here we report a simple route to design high-efficient WLEDs by combining a commercial ultraviolet LED chip (InGaAsN, 390 nm) and boehmite (γ-AlOOH) hybrid nanoplates. Unusually high quantum yields (ηyield=38-58%) result from a synergic energy transfer between the boehmite-related states and the triplet states of the benzoate ligands bound to the surface of the nanoplates. The nanoplates with ηyield=38% are able to emit white light with Commission International de l'Eclairage coordinates, colour-rendering index and correlated colour temperature values of (0.32, 0.33), 85.5 and 6,111 K, respectively; overwhelming state-of-the-art single-phase ultraviolet-pumped WLEDs phosphors.

The synthesis of a modular colloidal polymer system based on the dipolar assembly of CdSe@CdS nanorods functionalized with a single cobalt nanoparticle "tip" (CoNP-tip) is reported. These heterostructured nanorods spontaneously self-assembled via magnetic dipolar associations of the cobalt domains. In these assemblies, CdSe@CdS nanorods were carried as densely grafted side chain groups along the dipolar NP chain to form bottlebrush-type colloidal polymers. Nanorod side chains strongly affected the conformation of individual colloidal polymer bottlebrush chains and the morphology of thin films. Dipolar CoNP-tipped nanorods were then used as "colloidal monomers" to form mesoscopic assemblies reminiscent of traditional copolymers possessing segmented and statistical compositions. Investigation of the phase behavior of colloidal polymer blends revealed the formation of mesoscopic phase separated morphologies from segmented colloidal copolymers. These studies demonstrated the ability to control colloidal polymer composition and morphology in a manner observed for classical polymer systems by synthetic control of heterostructured nanorod structure and harnessing interparticle dipolar associations.

The acid-catalyzed reaction of 5-(hydroxymethyl)-2-furfural with ethanol is a promising route to produce biofuels or fuel additives within the carbohydrate platform; specifically, this reaction may give 5-ethoxymethylfurfural, 5-(ethoxymethyl)furfural diethylacetal, and/or ethyl levulinate (bioEs). It is shown that sulfonated, partially reduced graphene oxide (S-RGO) exhibits a more superior catalytic performance for the production of bioEs than several other acid catalysts, which include sulfonated carbons and the commercial acid resin Amberlyst-15, which has a much higher sulfonic acid content and stronger acidity. This was attributed to the cooperative effects of the sulfonic acid groups and other types of acid sites (e.g., carboxylic acids), and to the enhanced accessibility to the active sites as a result of the 2D structure. Moreover, the acidic functionalities bonded to the S-RGO surface were more stable under the catalytic reaction conditions than those of the other solids tested, which allowed its efficient reuse., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Starting with a discussion of the percolation problem applied to the trapping of conducting nanoparticles between nanometer-spaced electrodes, we show that a good strategy to trap a single nanoparticle between the electrodes is to prepare chips with low coverage of nanoparticles to avoid percolating current paths. To increase the probability of trapping a single nanoparticle, we developed a new method where nanoparticles are projected in-vacuum on the chip, followed by a measure of the tunnel current, in a cycle that is repeated up to a few thousand times until a preset threshold value is reached. A plot of the tunneling current as a function of time allows discriminating between the two possible current paths, i.e., a single nanoparticle trapped between the electrodes or a percolating path across many nanoparticles. We applied the method to prepare chip circuits with single gold nanoparticles, as demonstrated by the observation of Coulomb blockade. Furthermore, we applied the method to trap single magnetite nanoparticles for the study of electric-field-induced switching from insulator to metal in single nanoparticles.

Zirconia nanoparticles doped with Eu 3+ , Tb 3+ and Gd 3+ ions have been synthesized following the benzyl alcohol route. The nanoparticles were coated with N-hydroxydodecanamide and encapsulated in PLGA-b-PEG-COOH nanomicelles. The magnetic and fluorescent properties of these hybrid nanocarriers were investigated, proving them to be potential dual-imaging contrast agents.

A methodology providing access to dumbbell-tipped, metal-semiconductor and metal oxide-semiconductor heterostructured nanorods has been developed. The synthesis and characterization of CdSe@CdS nanorods incorporating ferromagnetic cobalt nanoinclusions at both nanorod termini (i.e., dumbbell morphology) are presented. The key step in the synthesis of these heterostructured nanorods was the decoration of CdSe@CdS nanorods with platinum nanoparticle tips, which promoted the deposition of metallic CoNPs onto Pt-tipped CdSe@CdS nanorods. Cobalt nanoparticle tips were then selectively oxidized to afford CdSe@CdS nanorods with cobalt oxide domains at both termini. In the case of longer cobalt-tipped nanorods, heterostructured nanorods were observed to self-organize into complex dipolar assemblies, which formed as a consequence of magnetic associations of terminal CoNP tips. Colloidal polymerization of these cobalt-tipped nanorods afforded fused nanorod assemblies from the oxidation of cobalt nanoparticle tips at the ends of nanorods via the nanoscale Kirkendall effect. Wurtzite CdS nanorods survived both the deposition of metallic CoNP tips and conversion into cobalt oxide phases, as confirmed by both XRD and HRTEM analysis. A series of CdSe@CdS nanorods of four different lengths ranging from 40 to 174 nm and comparable diameters (6-7 nm) were prepared and modified with both cobalt and cobalt oxide tips. The total synthesis of these heterostructured nanorods required five steps from commercially available reagents. Key synthetic considerations are discussed, with particular emphasis on reporting isolated yields of all intermediates and products from scale up of intermediate precursors.

We report a new method for deposition of Pt on a metal core to develop real electrocatalysts with significantly reduced amounts of expensive Pt as well as enhanced activity for oxygen reduction reaction. Ru and Pd have different crystal structures and modify the electronic structure of Pt to a different extent (shifts in d-band center). They were chosen as core materials to examine whether hydroquinone dissolved in ethanol can be used to deposit additional Pt atoms onto preformed core nanoparticles, and whether the modified d-character of Pt on different host metals can result in the enhanced ORR activity. The physicochemical characteristics of Pd-Pt and Ru-Pt core-shell nanoparticles are investigated. The core-shell structure was identified through a combination of experimental methods, employing electron microscopy, electrochemical measurements, and synchrotron X-ray measurements such as powder X-ray diffraction, X-ray absorption fine structure, and X-ray photoelectron spectroscopy. The hydroquinone reduction method proved to be an excellent route for the epitaxial growth of a Pt shell on the metal cores, leading to enhanced ORR activities.

A simple one-pot approach based on the "benzyl alcohol route" is introduced for the fabrication of highly ordered supercrystals composed of highly uniform 3-4 nm zirconia and rare-earth stabilized zirconia nanoparticles. The as-fabricated supercrystals reach sizes larger than 10 μm and present well-defined 3D morphologies such as flower-like, rhombic dodecahedron, and bipyramids. This system is unique in that the supercrystals are formed in one-step directly in the reaction medium where the nanoparticles are synthesized. The uniformity in nanocrystal shape and size is attributed to the in situ formation of benzoate species that directs the nanoparticle growth and assembly. The low colloidal stabilization of the benzoate-capped nanoparticles in benzyl alcohol promotes the formation of supercrystals in solution by π-π interaction between the in situ formed benzoate ligands attached to neighboring particles. By varying the reaction temperature and the nature of the doping the way the nanobulding blocks assemble in the supercrystals could be controlled. Standard FCC superlattice packings were found together with more unusual ones with P6/mmm and R ̅3m symmetries.

Atomic layer deposition (ALD) is a thin film technology that in the past two decades rapidly developed from a niche technology to an established method. It proved to be a key technology for the surface modification and the fabrication of complex nanostructured materials. In this Progress Report, after a short introduction to ALD and its chemistry, the versatility of the technique for the fabrication of novel functional materials will be discussed. Selected examples, focused on its use for the engineering of nanostructures targeting applications in energy conversion and storage, and on environmental issues, will be discussed. Finally, the challenges that ALD is now facing in terms of materials fabrication and processing will be also tackled., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Owing to the competition between the radiative and non-radiative decay channels occurring in plasmonic assemblies, we show here how to conceive a long pass emission filter and actually design it. We report the synthesis of gold@silica nanoparticles grafted with dye molecules. The control of the thickness of the silica shell allows us to tune the distance between the metal core and the dye molecules. Assemblies of small number (1 to 7) of these core-shell (CS) particles, considered as multimers, have also been produced for the first time. We show that the shaping of the emission spectra of the multimers is drastically enhanced by comparison with the corresponding monomers. We also show a strong enhancement of the decay rates at the LSP resonance, dominated by the non-radiative energy tranfer from the active medium to the metal. The decay rates decrease as the detuning between the long wavelength emission and the LSP resonance increases.

Luminescent TbPO4 nanoparticles were synthesized via a citric-acid-mediated hydrothermal route. Eu3+ doping of TbPO4 enables an efficient Tb3+-to-Eu3+ energy transfer, leading to a four-fold increase of the absolute emission quantum yield (QY), compared to that of undoped TbPO4. To check the potential of biological use, we conducted in vitro biological experiments on human cervical carcinoma HeLa cells incubated with TbPO4:Eu nanoparticles. TbPO4:Eu nanoparticles can be successfully internalized into the cells, and they show bright intracellular luminescence and very low cytotoxicity. Photoluminescence intensity dependence upon time demonstrates that Eu3+-doped TbPO4 nanoparticles are highly resistant to photobleaching. Our present work represents a demonstration of the use of rare-earth-based nanocrystals as a biological labeling agent because they combine several advantages including high emission quantum yield, long luminescence lifetime, low cytotoxicity and high photostability.

CoFe(2)O(4)-TiO(2) and CoFe(2)O(4)-ZnO nanoparticles/film composites were prepared from directed assembly of colloidal CoFe(2)O(4) in a Langmuir-Blodgett monolayer and atomic layer deposition (ALD) of an oxide (TiO(2) or ZnO). The combination of these two methods permits the use of well-defined nanoparticles from colloidal chemistry, their assembly on a large scale, and the control over the interface between a ferrimagnetic material (CoFe(2)O(4)) and a semiconductor (TiO(2) or ZnO). Using this approach, architectures can be assembled with a precise control from the Angstrom scale (ALD) to the micrometer scale (Langmuir-Blodgett film). The resulting heterostructures present well-calibrated thicknesses. Electron microscopy and magnetic measurement studies give evidence that the size of the nanoparticles and their intrinsic magnetic properties are not altered by the various steps involved in the synthesis process. Therefore, the approach is suitable to obtain a layered composite with a quasi-monodisperse layer of ferrimagnetic nanoparticles embedded in an ultrathin film of semiconducting material.

Surfactant-free nonaqueous (and/or nonhydrolytic) sol-gel routes constitute one of the most versatile and powerful synthesis methodologies for nanocrystalline metal oxides with high compositional homogeneity and purity. Although the synthesis protocols are particularly simple, involving only metal oxide precursors and common organic solvents, the obtained uniform nanocrystals exhibit an immense variety of sizes and shapes. The small number of reactants in these routes enables the study of the chemical mechanisms involved in metal oxide formation. Nonhydrolytic routes to inorganic nanomaterials that used surfactants as size- and shape-controlling agents have been discussed recently. This Minireview supplements this topic by discussing surfactant-free processes, which have become a valuable alternative to surfactant-assisted as well as to traditional aqueous sol-gel chemistry routes.

Nonhydrolytic sol-gel processes in organic solvents have become very popular for the synthesis of metal oxide NCs. We report an affordable, high-yield, shape-control synthesis of MnO multipod nanocrystals with a quick reaction time. The reaction yields exclusively multipods; two to six pod nanocrystals are synthesized. The mechanism leading to this hierarchical nanostructure is studied in relation with an oriented attachment mechanism; all nanocrystals are found to be single crystals. The study is completed by high-resolution TEM, X-ray powder diffraction, and magnetic measurements.

Nanoparticle powders composed of surface-functionalized anatase crystals with diameters of about 3 nm self-organize into different structures upon redispersion in water. The assembly is directed by a small amount of a low-molecular-weight functional ligand (the "assembler") adsorbed on the surface of the nanoparticles. The ligand functionality determines the anisotropy of the resulting structures. Multidentate ligands, such as trizma ((HOCH(2))(3)CNH(2)) and serinol ((HOCH(2))(2)CNH(2)), with a chargeable terminal group preferentially induce the formation of anisotropic nanostructures several hundreds of nanometers in total length, whereas all the other investigated ligands (ethanolamine H(2)N(CH(2))(2)OH, glycine hydroxamate H(2)NCH(2)CONHOH, dopamine (OH)(2)C(6)H(3)(CH(2))(2)NH(3)Cl, tris (HOCH(2))(3)CCH(3)) mainly lead to uncontrolled agglomeration. Experimental data suggests that the anisotropic assembly is a consequence of the water-promoted desorption of the organic ligands from the {001} faces of the crystalline building blocks together with the dissociative adsorption of water on these crystal faces. Both processes induce the preferred attachment of the titania nanoparticles along the [001] direction. The use of polydentate and charged ligands to functionalize the surface of nanoparticles thus provides a versatile tool to control their arrangement on the nanoscale.

Crystallization of DL-alanine by cooling of a supersaturated solution in the presence of a chiral double-hydrophilic block copolymer poly(ethylene glycol)-block-poly(ethylene imine)-S-isobutyric acid (PEG4700-PEI1200-S-iBAc) yields crystal superstructures with an astonishing morphology. Although analysis by light microscopy reveals these crystals to be apparently well facetted, electron microscopy shows that they consist of three-dimensionally, well-aligned nanocrystals that are scaffolded to a so-called mesocrystal. This mesocrystal is formed by polymer-mediated structuration, and provides evidence for the importance of mesoscopic events in a typical crystallization process.

A widely applicable solvothermal route to nanocrystalline iron, indium, gallium, and zinc oxide based on the reaction between the corresponding metal acetylacetonate as metal oxide precursor and benzylamine as solvent and reactant is presented. Detailed XRD, TEM, and Raman studies prove that, with the exception of the iron oxide system, where a mixture of the two phases magnetite and maghemite is formed, only phase pure materials are obtained, gamma-Ga(2)O(3), zincite ZnO, and cubic In(2)O(3). The particle sizes lie in the range of 15-20 nm for the iron, 10-15 nm for the indium, 2.5-3.5 nm for gallium, and around 20 nm for zinc oxide. GC-MS analysis of the final reaction solution after removal of the nanoparticles showed that the composition is rather complex consisting of more than eight different organic compounds. Based on the fact that N-isopropylidenebenzylamine, 4-benzylamino-3-penten-2-one, and N-benzylacetamide were the main species found, we propose a detailed formation mechanism encompassing solvolysis of the acetylacetonate ligand, involving C-C bond cleavage, as well as ketimine and aldol-like condensation steps.