Effect of preparation method on the properties of nanostructured gadolinia-doped ceria materials for IT-SOFCs

Abstract

In order to obtain different morphologies, nanostructured Gd 0.1Ce 0.9O 1.95 (GDC10) and Gd 0.2Ce 0.8O 1.90 (GDC20) were synthesized using three different chemical methods: reverse microemulsion (RM), cation complexation (CC) and template-filling (TF). The resulting materials were characterized by synchrotron radiation X-ray diffraction (SR-XRD), by X-ray absorption near-edge spectroscopy (XANES) and by scanning and high resolution transmission electron microscopy (SEM and HRTEM). All nanostructured mixed oxides were found to have a cubic crystal phase (Fm3m space group) with an average crystallite sizes ranging from 9.6 to 13.2 nm. Tubular nanostructured GDC10 obtained using a template-filling method exhibited the largest specific surface area (97 m 2 g -1) while the lowest values were obtained using the cation complexation method (23 m 2 g -1). XANES results indicated that the extent of reduction of these materials was small. Nevertheless, the Ce 3+ ion was detected. Preliminary catalytic studies showed that the tubular nanostructured (TF) GDC10 samples exhibited better catalytic activity for CH 4 oxidation than the CC and RM nanopowders of the same chemical composition.