Synthesis and characterization of pure-phase La0.75Sr0.25Cr0.5Mn0.5O32d nanocrystallites for solid oxide fuel cell applications
C. CHANQUIA; J. VEGA CASTILLO; A.L. SOLDATI; H. TROIANI; A. CANEIRO
JOURNAL OF NANOPARTICLE RESEARCH
Lugar: Berlin; Año: 2012
Nanopowders of La0.75Sr0.25Cr0.5Mn0.5O3-d (LSCM) perovskite-type oxide, potential electrodematerial for symmetrical solid oxide fuel cell(S-SOFC), have been successfully prepared by thesolution combustion method employing glycine ascomplexing agent and fuel. Several glycine-to-nitratesmolar ratios were investigated. A detailed morphologicaland structural characterization was performed,employing X-ray diffraction, N2 physisorption, andelectron microscopy (scanning and transmission). Theas-synthesized LSCM nanopowders consist of interconnectednanoparticles forming a sponge-like structurewith typical meso- and macropores. For glycineto-nitrates molar ratios above stoichiometric molarratio, a high proportion of well-crystallized LSCMphase was obtained. An increase of glycine content inthe initial synthesis gel, decreases the average nanoparticlessize from *20 to *6 nm, narrows thedistribution crystallite size, and increases the specificsurface area of the LSCM nanopowders from *14 to*30 m2/g. The evolution of crystalline phases of theas-synthesized LSCM nanopowders after calcinationat various temperatures was studied: pure-phaseLa0.75Sr0.25Cr0.5Mn0.5O3-d perovskites with particlesizedistribution between 100 and 300 nm, have beenobtained after calcination at 1,000 C for 6 h. Thecrystalline structural analyses showed that the LSCMnanocrystallites have trigonal/rhombohedral symmetryin the R-3c space group. These final LSCMnanopowders present microstructures with low densificationand open porosity but probably with sufficientintegrity to enable them to be used as efficientelectrodes in S-SOFC.