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Ferencz Z.,University of Szeged | Szabados M.,University of Szeged | Varga G.,University of Szeged | Csendes Z.,University of Szeged | And 7 more authors.
Journal of Solid State Chemistry | Year: 2016

A mechanochemical method (grinding the components without added water - dry grinding, followed by further grinding in the presence of minute amount of water or NaOH solution - wet grinding) was used in this work for the preparation and intercalation of CaFe-layered double hydroxides (LDHs). Both the pristine LDHs and the amino acid anion (cystinate and tyrosinate) intercalated varieties were prepared by the two-step grinding procedure in a mixer mill. By systematically changing the conditions of the preparation method, a set of parameters could be determined, which led to the formation of close to phase-pure LDH. The optimisation procedure was also applied for the intercalation processes of the amino acid anions. The resulting materials were structurally characterised by a range of methods (X-ray diffractometry, scanning electron microscopy, energy dispersive analysis, thermogravimetry, X-ray absorption and infra-red spectroscopies). It was proven that this simple mechanochemical procedure was able to produce complex organic-inorganic nanocomposites: LDHs intercalated with amino acid anions. © 2015 Elsevier Inc. All rights reserved.

Puskas R.,University of Szeged | Kukovecz A.,University of Szeged | Kukovecz A.,MTA SZTE Lendulet Porous Nanocomposites Research Group | Konya Z.,University of Szeged | Konya Z.,Surface Chemistry Research Group
Adsorption | Year: 2013

The size of carbon nanotube supported Pd and PdO nanoparticles was investigated on oxidatively functionalized multiwall carbon nanotubes. All samples were characterized by transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectroscopy and Raman spectroscopy. The average particle diameter calculated from TEM image analysis was found to be inversely proportional with the duration of the oxidation in nitric acid. Crystallite sizes determined from XRD patterns confirmed this general tendency. © 2013 Springer Science+Business Media New York.

Berko A.,Surface Chemistry Research Group | Gubo R.,University of Szeged | Ovari L.,Surface Chemistry Research Group | Bugyi L.,Surface Chemistry Research Group | And 3 more authors.
Langmuir | Year: 2013

Rh films of 5-50 monolayers (ML) were grown on TiO2(110)-(1 × 1) surface by physical vapor deposition (PVD) at 300 K followed by annealing at max. 1050 K. In the coverage range of 5-15 ML, separated stripe-like Rh nanoparticles of approximately 30 × 150 nm lateral size and 10-20 layer thickness with a flat top (111) facet were formed. At higher coverages (15-50 ML), the Rh film sustained its continuity at least up to 950 K. For both cases, the Rh(111) top facets were completely covered by a long-range ordered hexagonal "wagon-wheel" TiO1+x ultrathin oxide (hw-TiO-UTO) film. STM-STS, XPS, LEIS, and TDS methods were used for morphologic and electronic characterization of surfaces prepared in this way. The main part of this study is devoted to the study of postdeposition of Rh on the hw-TiO-UTO layer at different temperatures (230 K, 310 K, 500 K) and to the effect of subsequent annealing. It was found that 2D nanoparticles of 0.2-0.3 nm height and 1-2 nm diameter are formed at RT and their average lateral size increases gradually in the range of 300-900 K. The LEIS intensity data and the CO TDS titration of the particles have shown that an exchange of the postdeposited Rh atoms with the hw-TiO-UTO layer proceeds to an extent of around 50% at 230 K and this value increases up to 80-90% in the range of 300-500 K. The total disappearance of the characteristic LEIS signal for Rh takes place at around 900 K where a complete hw-TiO-UTO adlayer forms on top of the postdeposited metal (100% exchange). © 2013 American Chemical Society.

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