Oxygen mobility in microwave sintered praseodymium nickelates-cobaltites and their nanocomposites with Y-doped ceria
Functional Materials and Nanotechnologies Conference (FM&NT-2015)
05-08 Oct 2015
|| Sadykov Vladislav Aleksandrovich
, Eremeev Nikita Fedorovich
, Bolotov Vasiliy Aleksandrovich
, Tanashev Yury Yurʹevich
, Fedorova Yuliya E.
, Amanbaeva Dajana Galy'movna
, Bobin Alexey Sergeyevich
, Sadovskaya Ekaterina Mikhajlovna
, Muzykantov Vitalij Stepanovich
, Pelipenko Vladimir Valerʹevich
, Lukashevich Anton Igorevich
, Krieger Tamara Andreevna
, Ishchenko Arcady Vladimirovich
Boreskov Institute of Catalysis SB RAS
Novosibirsk State University
Novosibirsk State Technical University
Novosibirsk State Pedagogical University
PrNi1-xCoxO3-δ – Ce0.9Y0.1O2-δ composites are promising as IT SOFC cathodes provided their sintering conditions are optimized . In this work effect of microwave sintering (MS) on properties of such materials is studied.
Perovskite (P) PrNi0.5Co0.5O3-δ (PNC) and fluorite (F) Ce0.9Y0.1O2 (YDC) oxides were synthesized by Pechini route. PNC-YDC composites were prepared by ultrasonic dispersion. Pellets were sintered at 870 – 1100 °C using specially designed microwave set-up. Samples were characterized by XRD and TEM with EDX. Oxygen mobility was estimated by O2 TPD and oxygen isotope heteroexchange with 18O2 and C18O2.
MS provides dense materials (porosity < 10 %) even at the lowest temperatures. PNC is single-phase P. Composites are comprised of P+F phases with Pr6O11 admixture, strong elements redistribution between P and F domains occurs (Figure 1). The total amount of oxygen desorbed is up to 20 monolayers for PNC and 70 monolayers for PNC–YDC, being ~ 1.5 times higher as compared to conventionally sintered (CS) samples. This is due to a higher disordering of P and F domains as well as their boundaries. The oxygen isotope exchange is characterized by R2 mechanism with the surface exchange constant kex ~10 6 cm/s and the oxygen tracer diffusion coefficient DO ~10 8 cm2/s at 700 °C (Table 1), being close to CS samples made at higher temperatures .
Hence, MS at lower temperatures provides even better functional characteristics of PNC-YDC nanocomposite cathodes.