Oxygen mobility and surface reactivity of PrNi1−xCoxO3+δ–Ce0.9Y0.1O2−δ cathode nanocomposites

Temperature-programmed C18O2 SSITKA for powders of fast oxide-ion conductors: Estimation of oxygen self-diffusion coefficients

“…4) and conductivity measurements [4,6]. A rather moderate effect of the nature and content of Al and Fe dopants on the oxygen self-diffusion coefficient in apatites agrees with a similar weak effect of these parameters on the specific conductivity of these samples sintered at high temperatures into dense ceramics [7,9,12,13].…”

“…The temperature-programmed oxygen isotope exchange (temperature ramp 5°/min from 50 to 800°C) with 1% C 18 O 2 in He (O 2 admixture b 5 ppm) was carried out using kinetic installation with MS control of the gas phase composition. All details of experimental SSITKA procedures are given elsewhere [7][8][9]. For comparison, a sample of Sc 0.1 Ce 0.01 Zr 0.89 O 2 electrolyte (ScCeSZ, produced by DKKK, Japan, main characteristics were given in [11]) was studied as well.…”

“…on the transport properties of electrolytes and mixed ionicelectronic nanocomposites comprised of these electrolytes and electronic conductors (perovskites, etc.) [5][6][7][8][9]. For traditional 18 O 2 isotope heteroexchange on the oxide-ion conductors, the total process is often controlled by the surface exchange reaction, which makes impossible reliable estimation of D o without special procedures of the surface modification [4,7].…”

“…For traditional 18 O 2 isotope heteroexchange on the oxide-ion conductors, the total process is often controlled by the surface exchange reaction, which makes impossible reliable estimation of D o without special procedures of the surface modification [4,7]. Since the rate of CO 2 exchange on the surface of oxides is faster than that of O 2 , the experiments on the oxygen exchange between C 18 O 2 and powders of mixed ionic-electronic conducting perovskite-fluorite nanocomposites (La 1 − x Bi x MnO 3 + δ - [9]) in the flow reactor in so called SSITKA (Steady-State Isotope Transient Kinetics) mode allowed to estimate D o values with a reasonable precision. The temperature-programmed mode of C 18 O 2 exchange was shown to be much more sensitive to dynamics of the oxygen migration and the surface reaction, thus revealing coexistence of fast and slow paths of oxygen diffusion in PrNi 1 − x Co x O 3 − δ -Ce 0.9 Y 0.1 O 2− δ nanocomposites [9].…”

“…Since the rate of CO 2 exchange on the surface of oxides is faster than that of O 2 , the experiments on the oxygen exchange between C 18 O 2 and powders of mixed ionic-electronic conducting perovskite-fluorite nanocomposites (La 1 − x Bi x MnO 3 + δ - [9]) in the flow reactor in so called SSITKA (Steady-State Isotope Transient Kinetics) mode allowed to estimate D o values with a reasonable precision. The temperature-programmed mode of C 18 O 2 exchange was shown to be much more sensitive to dynamics of the oxygen migration and the surface reaction, thus revealing coexistence of fast and slow paths of oxygen diffusion in PrNi 1 − x Co x O 3 − δ -Ce 0.9 Y 0.1 O 2− δ nanocomposites [9]. However, this method still has not been applied for estimation of oxygen self-diffusion coefficients for pure solid electrolytes.…”