Low temperature synthesis and characterization of metal-oxide composites for gaseous liquid separation

S.A. OBREGÓN; M.R ESQUIVEL

Bariloche

Congreso; SPLG 2015; 2015

Comisión Nacional de Energía Atómica

It is presented the synthesis andcharacterization of La0.25Ce0.52Nd0.17Pr0.06O2/Ni/NiOmetal/oxide composites.  The processingconsists in two steps. The first one is the synthesis of an intermetallic ofthe CaCu5/P6/mmm type structure by mechanicalalloying at t < 150 °C. The second one is heating in air at controlled ratesand temperatures (T< 400 °C).   The nano and microstructure were characterizedby TEM and DRX. The structure is stable up to 160 ºC. Depending on theoperation temperature, the controlled formation of La0.25Ce0.52Nd0.17Pr0.06O2/Nicomposite is obtained up to 300 ºC. At higher temperatures, the kinetics isfaster and either La0.25Ce0.52Nd0.17Pr0.06O2(Fm3m)/Ni (Fm3m) or La0.25Ce0.52Nd0.17Pr0.06O2(Fm3m)/NiO(Fm3m)are formed. SEM/TEM measurements show a porous nanostructure. Crystallinefeatures of either member of the composite might be refined by changing theheating conditions after  thermal after decompositionas shown by XRD. No formation of mixed oxides is detected up to 800 ºC. Theobtained composite is suitable to be used in vapor/gas mixtures separation.First attempts in water/gas streams show good resistance of  the structure oxide/metal structure. Ifoxidized during treatment, the metal of filter can be recovered by treatmentunder H2 atmosphere as shown by RPT measurement with no furtherdamage to the La0.25Ce0.52Nd0.17Pr0.06O2structure.  Acknowledgements  The authors thanks CNEA, ANPCyT (PICT 0092 yPICT 0843), CONICET (PIP 0109) and UNComa (Project 04/B183) for partialfinancial suport. Keywords: metal oxide, gaseous separation,TEM, composites, Nanostructures.