Synthesis, Characterization, and Catalytic Behavior of Mg
Al
Zn
Fe Mixed Oxides from Precursors Layered Double Hydroxide

HEREDIA, A.C.; OLIVA, M. I.; ZANDALAZINI, C. I.; AGU, U.; EIMER, G. A.; CASUSCELLI, S. G.; HERRERO, E. R.; PEREZ, C.; CRIVELLO, M. E.

INDUSTRIAL & ENGINEERING CHEMICAL RESEARCH

AMER CHEMICAL SOC

Lugar: Washington; Año: 2010

0888-5885

In the present work, Mg-Al-Zn-Fe layered double hydroxides (LDH) were prepared by coprecipitation reaction with hydrothermal treatment. Their corresponding calcination products (mixed oxides) were used as catalyst for ethylbenzene dehydrogenation to styrene. The characterization of precursors and the mixed oxides was carried out by X rays diffraction, XPS, TGA-DSC, UV-vis-DRS, specific surface area and magnetic properties. The Fe3+ species were detected by XPS; they exist in two chemical states related to tetrahedral or octahedral environment. The zinc is found in two possible contributions, such as ZnO or spinel. XRD data indicate that the hydrotalcite phase exist in all samples, except for the sample without magnesium (HT100). In the mixed oxides the ZnO phase increases with the increase of the zinc content. Oxides show a decrease of surface areas with the increase of the zinc content. Ethylbenzene dehydrogenation was carried out with the mixed oxides synthesized. The HT25 sample shows a 31.5 % conversion and selectivity to styrene superior to 87%, which is directly related with the quantity of oxide, spinel phase and magnesium, as well as the high surface area and the paramagnetic response obtained.