Vilém Bartůněk

Affordable, Green, and Facile Synthesis of Copper Nanoparticles Stabilized by Environmentally Friendly Surfactants

Simple and affordable green synthesis of copper nanoparticles was developed. Nanoparticles of various sizes were prepared using the solvothermal reduction method in glycerol, which acted as both a solvent and a reduction agent. The nanoparticles had average diameters of 38 to 50 nm and were characterized by X-ray powder diffraction, transmission electron microscopy, and ultraviolet–visible spectroscopy. Affordable surfactants based on polyethylene glycols PEG200, PEG6000, and PEG20000 and Polysorbate 80 were used for stabilization of the nanoparticles. All precursors were nontoxic, environmentally friendly substances, and the method is usable even for preparation of large quantities of product. Therefore, it could be useful for various applications even on industrial scale and could provide useful alternatives to more expensive or environmentally dangerous methods.Graphical Abstract

Preparation of manganese oxide nanoparticles by thermal decomposition of nanostructured manganese carbonate

MnO and Mn2O3 nanoparticles were prepared in air and argon atmosphere by thermal decomposition of nanocrystalline manganese carbonate synthesized by reaction of manganese(II) nitrate with glycerol. Samples were characterized using transmission electron microscopy, simultaneous thermal analysis and X-ray diffraction analysis. Average sizes of prepared nanoparticles were calculated from XRD patterns using Scherrer equation. Also, the conditions for decomposition of manganese carbonate were optimized to obtain optimal nanoparticle sizes. Due to suitable sizes of prepared nanoparticles and the initial material, this method can be used in a wide range of industrial applications.

Synthesis of Ultrafine Metallic Copper Nanocubes Using Ethanol-Ionic Liquid Approach

Ultrafine metallic copper nano-cubes were synthesized by reduction of copper nitrate by superheated ethanol in 1-Butyl-3-methylimidazolium hexafluorophosphate ionic liquid environment. Nanocubes were characterized by X-ray powder diffraction, transition electron microscopy and X-ray photoelectron spectroscopy. Since all resources are environmentally-friendly substances, the presented procedure is highly sustainable and may be useful for numerous applications.

Preparation of surfaces of composite samples for tip based micro-analyses using ion beam milling

Ion beam milling, as a method of surface design for tip analytical techniques, was explored. A sample of clay, embedded in a resin, was treated by the ion beam and allowed AFM (a typical tip technique) to be successfully applied. The method is suitable for advanced tip analyses based on AFM, like TERS or SNOM, and for samples that are not possible to prepare by standard mechanical methods. The approach can be useful for characterisation of the surfaces of many different types of materials in versatile applications such as catalysis, corrosion science or advanced material characterisation.

Synthesis of YBCO - Y-2411-M (M=Bi, Mo, Nb, Ta, Ti and Zr) superconducting composites by TSMG

YBa2Cu3O7-δ (YBCO) is a well-known high-temperature superconductor (HTS), whose properties can be improved significantly via flux pinning. In this contribution, we have attempted to synthesize Y-2411-M (Y2Ba4CuMOx; M=Bi, Mo, Nb, Ta, Ti and Zr) phases by solid state reaction to serve as artificial pinning centers in YBCO. We discuss both the synthesis of Y-2411-M phases as well as the final Y-2411-M ceramic composites based on YBCO matrix. Phases and precursors were analyzed using X-ray diffraction analysis (XRD) and Rietveld analysis was performed to refine the lattice parameters. Promising phases were used for growth of single crystals using top-seeded melt growth (TSMG). These bulks were further characterized using XRD, scanning electron microscopy (SEM) to provide context to their structure – properties relationship. Thermal stability of the successfully prepared bulks was studied using STA.YBa2Cu3O7-δ (YBCO) is a well-known high-temperature superconductor (HTS), whose properties can be improved significantly via flux pinning. In this contribution, we have attempted to synthesize Y-2411-M (Y2Ba4CuMOx; M=Bi, Mo, Nb, Ta, Ti and Zr) phases by solid state reaction to serve as artificial pinning centers in YBCO. We discuss both the synthesis of Y-2411-M phases as well as the final Y-2411-M ceramic composites based on YBCO matrix. Phases and precursors were analyzed using X-ray diffraction analysis (XRD) and Rietveld analysis was performed to refine the lattice parameters. Promising phases were used for growth of single crystals using top-seeded melt growth (TSMG). These bulks were further characterized using XRD, scanning electron microscopy (SEM) to provide context to their structure – properties relationship. Thermal stability of the successfully prepared bulks was studied using STA.

Synthesis and Properties of Nanosized Stoichiometric Cobalt Ferrite Spinel

Nanoparticles with controllable sizes of ferrite spinel CoFe2O4 were formed by thermal treatment of cobalt-iron glycerolate. Thermal behavior during the heating was studied by differential thermal analysis combined with thermogravimetry. The precursor, as well as the prepared nanoparticles, were analyzed by a broad spectrum of analytic techniques (X-Ray photoelectron spectroscopy (XPS), X-Ray diffraction (XRD), Energy dispersive spectroscopy (EDS), Atomic absorption spectroscopy (AAS), Scanning electron microscopy (SEM), and Raman spectroscopy). The particle size of nanoparticles was obtained from Transmission electron microscopy and also calculated using Scherrer formula. A vibrating sample magnetometer (VSM) in a Physical Property Measurement System was used to analyze the magnetic properties of nanoparticles.

Mixed Yttrium–Ytterbium–Erbium Schiff Base Complex as a Model Precursor for Mixed Nanosized Rare Earths Oxides

Novel mixed rare-earth complex of Y, Yb and Er with Schiff base ligand PL–AlaK was synthesized and characterized in detail by a wide spectrum of analytic techniques such as UV–Vis spectroscopy, Fourier-transform infrared spectroscopy, elemental analysis (CHNS–O) and energy dispersive spectroscopy (EDS) measurements. Thermal properties of Y–Er–Yb–PL–Ala complex were studied using simultaneous thermal analysis. Product of thermal decomposition, nanosized mixed oxide was characterized by EDS, X-ray powder diffraction and by transmission electron microscopy. The approach may be used for various template syntheses of optical active nanomaterials, for assembling of nanocomposites or synthesis of various doped REs nanomaterials.

Carbon tape microsampling for non-destructive analyses of artefacts

Recent advances in analytical tools enable more effective investigation of archaeological artefacts, artwork and objects of cultural heritage. Obtained information may reveal possible manufacturing methods as well as important data on distribution, usage and discard of the artefacts. For example, Raman microscopy (Clark 2007) is one of the recent methods contributing to this field. SEM-EDS (scanning electron microscopyenergy-dispersive X-ray spectroscopy) is one of the most promising methods enabling to study very small samples. Although there are some early attempts aimed at application of these methods (Freestone and Middleton 1987), their true utilisation is quite recent due to broader availability of the techniques in research institutions. Therefore, this powerful analytical tool is used to examination of large family of objects ranging from prehistoric shell tools (Tumung et al. 2015), archaeometallurgical materials (Ashkenazi et al. 2011; Ashkenazi et al. 2013; Ashkenazi et al. 2012; Iles and Lane 2015) and ceramic fragments (Medeghini et al. 2016; Nagy et al. 2015; Weiss et al. 2016) to medieval illuminated parchments (Duran et al. 2014). In this text, we reveal our approach to collection of microsamples from surfaces of early medieval moulds for casting ingots found at Vyšehrad castle which together with Prague castle constituted supreme Bohemian fortified central places in 10–12 century. The moulds represent highly valuable artefacts due to the fact that they are the only ones found so far from the region and period of the emerging Czech state. For this reason, to understand what metals were casted in these artefacts, we aimed at applying only non-destructive analysis. However, as proportions of most of archaeological artefacts usually do not fit in the chambers of commonly available electronmicroscopes and shapes of the artefacts are frequently too curvy to applying scanning methods, the scientists are forced to decide whether to destroy them or leave them out of the particular analysis. Formerly, we were facing exactly the same problem because the direct measurements by electron microscope we had conducted before applying the approach handled below allowed us only to collect data from lateral sections of the working areas of one of the moulds that could provide probably only incomplete results [5]. Our technique is useful in the first place for the SEM-EDS analyses as we demonstrate but may be applied also for various other analytical tools operating with micro-amounts.