Vitalii Muzykantov

La0.8Sr0.2Ni0.4Fe0.6O3–Ce0.8Gd0.2O2–δ Nanocomposite as Mixed Ionic–Electronic Conducting Material for SOFC Cathode and Oxygen Permeable Membranes: Synthesis and Properties

Mixed ionic–electronic conducting nanocomposite La0.8Sr0.2Ni0.4Fe0.6O3 (LSNF)–Ce0.8Gd0.2O2– δ (GDC) was prepared via ultrasonic dispersion of nanocrystalline powders of perovskite and fluorite oxides in water with addition of surfactant, followed by drying and sintering up to 1300°C. Analysis of the real structure of nanocomposite (studied by XRD and TEM with EDX) and its surface composition (studied by XPS) revealed moderate redistribution of elements between phases favoring their epitaxy. Results of impedance spectroscopy, oxygen isotope exchange, O2 TPD and H2 TPR experiments revealed a positive effect of composite interfaces on the oxygen mobility and reactivity agreeing with the ambipolar transport behavior of MIEC composite. Preliminary testing of button-size cell with functionally graded LSNF–GDC cathode layer supported on thin YSZ layer covering Ni/YSZ cermet demonstrated high and stable performance, which is promising for its practical application.

Doped Nanocrystalline Pt-Promoted Ceria-Zirconia as Anode Catalysts for IT SOFC: Synthesis and Properties

Ceria-zirconia samples doped with Gd, Pr, Sm, or La cations were prepared via Pechini route and promoted by Pt. Effect of their real structure and surface properties (characterized by neutronography, EXAFS, XPS, FTIRS of adsorbed CO) on the mobility and reactivity of the lattice oxygen (by oxygen isotope exchange and CH 4 TPR) was analyzed. For the reaction of CH 4 steam reforming (SR), catalytic performance is determined both by Pt dispersion and lattice oxygen mobility. Ni-YSZ anodes promoted by these catalysts possess a stable and efficient performance in CH 4 SR in the 600-800°C range in stoichiometric feeds without coking.

Interpretation of Isotope Exchange Data “without Time”: Nonisothermal Exchange of Dioxygen with Oxides1

As a result of transformation of isotope-exchange rate equations (isotope-kinetic equations), a relationship was derived that does not contain time and universally relates the variables of isotope composition (an isotope-mechanistic equation). With the use of this relationship, mechanistic parameters that characterize atomic rearrangements can be determined from experimental data even in cases when the rate of exchange varied in the course of a process, for example, under nonisothermal conditions. The use of the proposed approach for the treatment of the results of dynamic thermal isotope exchange in the O2–YBa2Cu3Oy and O2–Pt/CeZrO systems demonstrated that the experimental data were excellently described by the theoretical equation derived in this work

Design and Characterization of Nanocomposites Based on Complex Perovskites and Doped Ceria as Advanced Materials for Solid Oxide Fuel Cell Cathodes and Membranes

La 0.8 Sr 0.2 Fe 0.6 Ni 0.4 O 3-x - Ce 0.9 Gd 0.1 O 2-x and La 0.8 Sr 0.2 Fe 0.8 Co 0.2 O 3-x - Ce 0.9 Gd 0.1 O 2-x nanocomposites were synthesized via ultrasonic dispersion of nanocrystalline powders of perovskite and fluorite oxides in acetone with addition of a surfactant, followed by drying and sintering at temperatures up to 1200°C. The evolution of the structure of samples with sintering temperature was studied by XRD and TEM with EDX and compared with the data on conductivity, oxygen isotope exchange, O 2 TPD, H 2 and CH 4 TPR. Preliminary testing of button-size cells with cathodes supported on thin YSZ layer covering Ni/YSZ cermet demonstrated a high and stable performance of LSNF–GDC composite promising for the practical application.

Specificity of the Local Structure of Nanocrystalline Doped Ceria Solid Electrolytes

This work presents results of studies of the structural features of nanocrystalline doped Ce1xMexO2-y samples (Me = Sm, Bi, Gd; x = 0-0.5) prepared via the polymerised precursor (Pechini) route by using a combination of diffraction (XRD, TEM, WAXS on SR) and spectroscopic (EXAFS, Raman, FTIRS of lattice modes, XPS, SIMS) methods.

Perovskite and Composite Materials for Intermediate Temperatures Solid Oxide Fuel Cells

La 0.8 Sr 0.2 Fe 0.6 Ni 0.4 O 2.9 (LSFN) and LSFN-La 9.83 Si 4.5 Fe 1.5 O 26 (LSiF) nanocomposite were synthesized and investigated as cathode materials for intermediate temperature (IT) solid oxide fuel cells (SOFC). Phase and structure evolution with sample sintering temperature as well as their transport properties and catalytic activity in oxygen reduction were studied.