Formation Studies on the Nonaqueous Synthesis of Metal Oxide Nanoparticles in a 1.5 L Reactor System

In the last years, the nonaqueous synthesis has been demonstrated as a highly versatile method for the simple synthesis of highly crystalline metal oxide nanoparticles and nanomaterials. Thereby, we have presented the synthesis of a multitude of different metal oxides (e.g., TiO2, ZrO2, BaTiO3, Fe3O4). The mechanisms of particle formation as well as the influence of process parameters on the particle properties however remain largely unknown so far, as the molecular mechanisms are rather complex. In this paper, we show that the synthesis of metal oxide nanoparticles is feasible also on a multi-gram reactor scale on the example of anatase TiO2 nanoparticles. Using a reactor system equipped with a sampling system for with-drawal of samples at different stages of the reaction, the kinetics of particle formation could be determined and compared to the formation of organic side products and water. Additionally, insights into the influence of different process parameters on the particle properties are shown and can be utilized to tailor size and morphology of the product nanoparticles. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3489

Fractal growth of ZrO2 nanoparticles induced by synthesis conditions

Strong changes in morphology and phase composition of zirconia nanoparticles can be induced by altering the growth conditions during nanoparticle synthesis. Here, we demonstrate that fractal ZrO2 nanocrystals showing high specific surface area can be obtained in the nonaqueous synthesis by variation of temperature and precursor concentration. The growth process was studied in detail revealing a size increase from 2.7 to 7 nm as well as a change in the polymorphic composition from tetragonal to monoclinic zirconia. TEM measurements of samples withdrawn over the course of the synthesis showed that particles grow from roundish to dendritic shapes during the phase transformation. In contrast to the common assumption that the phase transition is controlled by thermodynamics, our data shows that the transition is rather governed by kinetics. © The Royal Society of Chemistry 2016

Formation of Aluminum-Doped Zinc Oxide Nanocrystals via the Benzylamine Route at Low Reaction Kinetics

The influence of essential process parameters on the adjustability of specific process and particulate properties of aluminum‐doped zinc oxide (AZO) nanocrystals during synthesis via the benzylamine route at low reaction kinetics is demonstrated by enabling time‐resolved access of the selected measurement technique. It is shown that the validity of the pseudo‐first‐order process kinetics could be extended to the minimum operable reaction kinetics. On the other hand, the impacts of the process temperature and the initial precursor concentration on both the process kinetics and the particle morphology are discussed. The obtained data provide a versatile tool for precise process control by adjusting defined application‐specific particle properties of AZO during synthesis

Effect of the anionic counterpart: Molybdate vs. tungstate in energy storage for pseudo-capacitor applications

Nickel-based bimetallic oxides (BMOs) have shown significant potential in battery-type electrodes for pseudo-capacitors given their ability to facilitate redox reactions. In this work, two bimetallic oxides, NiMoO4 and NiWO4, were synthesized using a wet chemical route. The structure and electrochemical properties of the pseudo-capacitor cathode materials were characterized. NiMoO4 showed superior charge storage performance in comparison to NiWO4, exhibiting a discharge capacitance of 124 and 77 F·g−1, respectively. NiMoO4, moreover, demonstrates better capacity retention after 1000 cycles with 87.14% compared to 82.22% for NiWO4. The lower electrochemical performance of the latter was identified to result from the redox behavior during cycling. NiWO4 reacts in the alkaline solution and forms a passivation layer composed of WO3 on the electrode, while in contrast, the redox behavior of NiMoO4 is fully reversible

Rapid Microfluidic Preparation of Niosomes for Targeted Drug Delivery

Niosomes are non-ionic surfactant-based vesicles with high promise for drug delivery applications. They can be rapidly prepared via microfluidics, allowing their reproducible production without the need of a subsequent size reduction step, by controlled mixing of two miscible phases of an organic (lipids dissolved in alcohol) and an aqueous solution in a microchannel. The control of niosome properties and the implementation of more complex functions, however, thus far are largely unknown for this method. Here we investigate microfluidics-based manufacturing of topotecan (TPT)-loaded polyethylene glycolated niosomes (PEGNIO). The flow rate ratio of the organic and aqueous phases was varied and optimized. Furthermore, the surface of TPT-loaded PEGNIO was modified with a tumor homing and penetrating peptide (tLyp-1). The designed nanoparticular drug delivery system composed of PEGNIO-TPT-tLyp-1 was fabricated for the first time via microfluidics in this study. The physicochemical properties were determined through dynamic light scattering (DLS) and zeta potential analysis. In vitro studies of the obtained formulations were performed on human glioblastoma (U87) cells. The results clearly indicated that tLyp-1-functionalized TPT-loaded niosomes could significantly improve anti-glioma treatment