Morphology and Structure of Zirconia-ceria based Nanopowders Synthesised by Nitrates-EDTA and Nitrates-TRIS Gel-combustion Routes

Abstract

Gel-combustion syntheses (GCPs) employing different fuels are widely recognized in the literature because of their versatility, low cost and experimental flexibility. Besides, they allow to obtain a large amount of a pure, homogeneous nanopowder in a single batch process.In a previous work the authors reported new GCPs for zirconia-ceria nanopowders, syntheses based on nitrates-EDTA and nitrates-TRIS and preliminary results of morphology and structures of the different, obtained powders calcined at selected temperatures. In this article, new results about morphological and structural characterization of nanopowders obtained by fuel-rich and stoichiometric, nitrates-EDTA and nitrates-TRIS GCPs, mainly calcined at 600°C/2h, are informed. The characterizations were performed by SEM, TEM, DRX and SBET techniques.By XRD, the expected retention of the metastable, tetragonal phase was established in ZrO2-rich, calcined nanopowders (ZrO2-15mol%CeO2), meanwhile, in CeO2-rich, calcined nanopowders (ZrO2-90mol%CeO2) the usually expected, thermodynamically stable, cubic phase was obtained.By SEM, typical agglomerates of variable morphology were observed, depending on the GCP/composition choice. By TEM the detailed nanostructure of the nanocrystallites aggregation was observed.In all cases, single-phased, homogeneous in composition, nanostructured powders were obtained. Some of them exhibit excellent properties, such as medium-high range specific surface area, for potential application in catalysis and SOFC technology.