The crystal structure of Ce0.8Gd0.1Ho0.1O1.9 (cerium gadolinium holmium oxide) has been determined from powder X-ray diffraction data. This is a promising material for application as a solid electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Nanoparticles were prepared using a novel sodium alginate sol-gel method, where the sodium ion was exchanged with ions of interest and, after washing, the gel was calcined at 723 K in air. The crystallographic features of Gd and Ho co-doped cerium oxide were investigated around the desired operating temperatures of IT-SOFCs, i.e. 573 ≤ T ≤ 1023 K. We find that the crystal structure is a stable fluorite structure with the space group Fm-3m in the entire temperature range. In addition, the trend in lattice parameters shows that there is a monotonic increase with increasing temperature.
Keywords: IT-SOFC; cerium; co-doping; crystal structure; fluorite; gadolinium; holmium; in situ X-ray diffraction; intermediate-temperature solid oxide fuel cells; powder diffraction; rare earth oxides; solid electrolyte.