National Institute Of Materials Physics - Romania

Publications

161 articles found

121. Modifications of the Catalytic Activity for Cyanoethylation Induced by the Memory Effect of Mg/Al-Type Modified Hydrotalcites

Authors: Pavel, OD; Birjega, R; Angelescu, E; Zavoianu, R; Florea, M; Mitran, G

Published: APR 2010, , DOI:

122. Epoxidation of cyclohexene with O-2 and isobutyraldehyde catalysed by cobalt modified hydrotalcites

Authors: Angelescu, E; Ionescu, R; Pavel, OD; Zavoianu, R; Birjega, R; Luculescu, CR; Florea, M; Olar, R

Published: JAN 15 2010, , DOI: 10.1016/j.molcata.2009.09.009

123. Local environment of vanadium in V/Al/O-mixed oxide catalyst for propane ammoxidation: Characterization by in situ valence-to-core X-ray emission spectroscopy and X-ray absorption spectroscopy

Authors: Safonova, OV; Florea, M; Bilde, J; Delichere, P; Millet, JMM

Published: NOV 15 2009, , DOI: 10.1016/j.jcat.2009.09.014

124. Transesterification of vegetable oils on basic large mesoporous alumina supported alkaline fluorides-Evidences of the nature of the active site and catalytic performances

Authors: Verziu, M; Florea, M; Simon, S; Simon, V; Filip, P; Parvulescu, VI; Hardacre, C

Published: APR 1 2009, , DOI: 10.1016/j.jcat.2009.01.012

125. Total oxidation of toluene on ferrite-type catalysts

Authors: Florea, M; Alifanti, M; Parvulescu, VI; Mihaila-Tarabasanu, D; Diamandescu, L; Feder, M; Negrila, C; Frunza, L

Published: MAR 30 2009, CATALYSIS TODAY, 141, 366, DOI: 10.1016/j.cattod.2008.05.005

Ferrite catalysts were prepared following two routes, i.e. the hydrothermal one and the calcination of an oxide mixture. In the first route sodium hydroxide, ferrous sulfate and the sulfate of the substituting ion (Mn, Ni) were used. The ferrites obtained using this route was NixFe3-xO4 (x = 0.5) and MnxFe3-xO4 (x similar to 0.65). Following the second route were prepared three samples: NiFe2O4, Ni0.5Zn0.5Fe2O4 and MnFe2O4. Two of them contain the corresponding ferrites while the latter is a presintered oxide mixture (Fe2O3-Mn2O3). All the samples were fully characterized using chemical analysis, X-ray fluorescence spectroscopy and EDX, nitrogen adsorption-desorption isotherms at -196 degrees C, X-ray diffraction (XRD), FTIR, scanning electron microscopy and XPS. The catalytic activity evaluation was made using a mixture of 1700 ppm vol. of toluene and air flowing at 100 ml min(-1) raising the temperature up to 600 degrees C in steps of 25 degrees C. Among these systems the sample representing the presintered Fe2O3-Mn2O3 mixture showed the highest activity. (C) 2008 Elsevier B.V. All rights reserved.

126. Iron oxide colloids and their heterogenization by silica sol-gel entrapment: Catalytic and magnetic properties

Authors: Neatu, F; Kraynov, A; D'Souza, L; Parvulescu, VI; Kranjc, K; Kocevar, M; Kuncser, V; Richards, R

Published: AUG 31 2008, APPLIED CATALYSIS A-GENERAL, 346, 35, DOI: 10.1016/j.apcata.2008.04.024

Fe3O4 colloids modified by the chiral ligand cinchonidine were prepared with the goal of obtaining a magnetic and catalytic nano-material and were subsequently embedded in silica to form a heterogeneous catalyst. The systems were characterized by TEM and XRD measurements, while the Mossbauer technique was applied for measuring the magnetic properties of the Fe3O4 colloids. The hyperfine magnetic field distribution was consistent with one type of Fe oxide, namely, the magnetite (Fe304). These colloids, both as 'quasi-homogenous catalysts' (or soluble heterogeneous catalysts) and embedded in silica (heterogeneous catalysts) were employed in the selective hydrogenolysis of complex bicyclo[2.2.2]oct-7-enes (bicyclo[2.2.2]oct-2-enes when unsubstituted). (C) 2008 Published by Elsevier B.V.

127. The impact of the "memory effect" on the catalytic activity of Mg/Al; Mg,Zn/Al; Mg/Al,Ga hydrotalcite-like compounds used as catalysts for cycloxene epoxidation

Authors: Angelescu, E; Pavel, OD; Birjega, R; Florea, M; Zavoianu, R

Published: JUN 15 2008, , DOI: 10.1016/j.apcata.2007.12.022

128. WO(x)-CeO(2) and WO(x)-Nb(2)O(5) catalysts deactivation during hexane isomerization

Authors: Mamede, AS; Payen, E; Granger, P; Florea, M; Parvulescu, VI

Published: MAY 2008, , DOI: 10.1002/aic.11468

129. Mo-V-M-O (M = Ni, Cu, Zn, Sb, Ta) MIXED METAL OXIDES PREPARED BY SOLID-SOLID REACTIONS FOR OXIDATIVE DEHYDROGENATION OF ISOBUTANE

Authors: Mitran, G; Marcu, IC; Florea, M; Sandulescu, I

Published: MAY 2008, , DOI:

130. Plasma-assisted catalysis total oxidation of trichloroethylene over gold nano-particles embedded in SBA-15 catalysts

Authors: Magureanu, M; Mandache, NB; Hu, JC; Richards, R; Florea, M; Parvulescu, VI

Published: NOV 15 2007, , DOI: 10.1016/j.apcatb.2007.05.030