Synthesis and characterization of pure-phase La0.75Sr0.25Cr0.5Mn0.5O3-d nanocrystallites for solid oxide fuel cell applications

CHANQUÍA, CORINA; VEGA CASTILLO, JESÚS; SOLDATI, ANALIA L.; TROIANI, HORACIO; CANEIRO, ALBERTO

JOURNAL OF NANOPARTICLE RESEARCH

SPRINGER

Lugar: Berlin; Año: 2012 vol. 14 p. 1104 - 1118

1388-0764

Nanopowders of La0.75Sr0.25Cr0.5Mn0.5O3-d (LSCM) perovskite-type oxide, potential electrode material for symmetrical solid oxide fuel cell (S-SOFC), have been successfully prepared by the solution combustion method employing glycine as complexing agent and fuel. Several glycine-to-nitrates molar ratios were investigated. A detailed morphological and structural characterization was performed, employing X-ray diffraction, N2 physisorption, andelectron microscopy (scanning and transmission). The as-synthesized LSCM nanopowders consist of interconnected nanoparticles forming a sponge-like structure with typical meso- and macropores. For glycineto-nitrates molar ratios above stoichiometric molar ratio, a high proportion of well-crystallized LSCM phase was obtained. An increase of glycine content inthe initial synthesis gel, decreases the average nanoparticles size from *20 to *6 nm, narrows thedistribution crystallite size, and increases the specific surface area of the LSCM nanopowders from *14 to *30 m2/g. The evolution of crystalline phases of the as-synthesized LSCM nanopowders after calcination at various temperatures was studied: pure-phaseLa0.75Sr0.25Cr0.5Mn0.5O3-d perovskites with particlesize distribution between 100 and 300 nm, have been obtained after calcination at 1,000 C for 6 h. The crystalline structural analyses showed that the LSCM nanocrystallites have trigonal/rhombohedral symmetryin the R-3c space group. These final LSCM nanopowders present microstructures with low densification and open porosity but probably with sufficient integrity to enable them to be used as efficient electrodes in S-SOFC.