Nanocomposite cermet materials comprised of NiO/YSZ (20-90 wt. %) co-promoted with SmPrCeZrO or LaPrMnCrO complex oxides and Pt, Pd or Ru were synthesized by Pechini method. These materials were characterized by BET, TEM with EDX, and CH4 TPR. The catalytic properties were studied for the steam reforming (SR) of CH4 at short contact times. Factors controlling performance of these composites in CH4 SR (Ni content, interaction between components in composites as dependent upon their chemical composition) were determined. Ru-promoted composite supported on Ni-Al foam demonstrated a high (up to 75%) methane conversion at 650° in the feed containing 20% CH4 and 40% H2O in Ar

SSZ-based ceramics were obtained by sintering of nanopowders derived at room temperature by mechanochemical synthesis from refined technical grade ZrO2 nano-precursors. RT-treatment by 2.5 MeV electrons up to 1563 K was used for the modification of ceramics. Powders and ceramics were characterized by XRD, Raman, SEM and EDS, TEM, SIMS techniques. The phase composition of Zr0.89Sc0.1Ce0.01O1.95 ceramics was very close to cubic structure but better fitting of XRD patterns was obtained for rhombohedral lattice. Conductivity of solid electrolytes for IT SOFC was studied by complex impedance method. To stabilize cubic structure and increase conductivity at operation temperature of To ∼ 1000 K, the composition of SSZ solid electrolyte was optimized by addition of yttria and sintering aids. The interaction of admixtures with minor dopants leading to intergrain phase was revealed. During fast sintering, ceramics keep a memory about inhomogeneous disordered solid solutions in a form of nanostructuring. Conductivity data indicate nanostructuring of ceramics too: activation energies of bulk and grain boundary conductivities are close (Eb ∼ 0.9 eV, Egb ∼ 1.05 eV). Annealing of ceramics at high temperatures increases conductivity at To and promotes grain growth.

This work considers effect of type and content of dopant on the real structure, state of surface Pt species and oxygen mobility of nanocrystalline Lnx(Ce0.5Zr0.5)1-xO2-δ (Ln=La3+, Gd3+, Pr3+/4+) solid solutions prepared by Pechini route. For the reactions of methane selective oxidation and dry reforming into syngas, catalytic activity correlates rather well with either surface (in diluted feeds) or bulk (in realistic feeds) oxygen mobility as well as Pt dispersion controlled by the type and content of a dopant.

Structural features and transport properties of Fe- and Al-doped apatite-type lanthanum silicates were studied with relation to a role of the [SiO4] substructure. XRD, TEM, Mössbauer, UV-Vis electron, IR, 29Si and 27Al NMR spectroscopy were used for structural studies; impedance spectroscopy and oxygen isotope heteroexchange were used for transport properties characterization.

La0.8Sr0.2Fe0.6Ni0.4O3-x - Ce0.9Gd0.1O2-x and La0.8Sr0.2Fe0.8Co0.2O3-x - Ce0.9Gd0.1O2-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, O2 TPD, H2 and CH4 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.

Composite materials based on NiO and doped apatite-type lanthanum silicates (ATLS) that are new class of solid electrolytes were studied as anode materials for intermediate temperature solid oxide fuel cells (IT SOFC), with possibility to use both H2 and CH4 as a fuel being payed attention to. For cermets preparation different methods of Ni addition such as incipient wetness impregnation, modified Pechini methods or mechanical mixing were used. The composite materials were characterized by XRD, BET, TPO and methane steam reforming reaction. Doping with complex oxides possessing a high mobility of the lattice oxygen and partial Ni substitution by the mixed conductor were applied to improve anode stability to coking.

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 CH4 TPR) was analyzed. For the reaction of CH4 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 CH4 SR in the 600-800°C range in stoichiometric feeds without coking.

Nanocrystalline ceria-zirconia samples doped with rare-earth (Gd, Pr, Sm, La) cations were prepared via modified Pechini route. Effect of their real structure and surface composition characterized by a combination of sophisticated physical methods (XRD, TEM +EDX, EXAFS, WAXS, UV-Vis, XPS, SIMS) on the mobility and reactivity of the lattice oxygen estimated by oxygen isotope exchange, H2, CH4 and CO TPR was analyzed. For the reaction of acetone autothermal reforming into syngas, catalytic activity correlates rather well with the oxygen mobility controlled by the type and content of a dopant

Effect of fluorite-like or perovskite-like complex oxide promoters and Pd on the performance of Ni/YSZ and Ni/ScSZ cermets in methane steam reforming or selective oxidation by O2 into syngas at short contact times was studied. Spatial uniformity of dopants distribution in composites was controlled by TEM combined with EDX, while the lattice oxygen mobility and reactivity was elucidated by CH4 and H2 TPR. Oxide promoters allow to operate even at stoichiometric H2O/CH4 ratio by suppressing coke deposition through modification of Ni surface, while doping by Pd ensures reasonable performance at moderate (∼550 °C) temperatures required for Intermediate–Temperature Solid Oxide Fuel Cells (IT SOFC).

Modeling of high resolution nitrogen adsorption isotherms by the Grand Canonical Monte Carlo (GCMC) method for zirconia-pillared clays containing 20 wt.% of ZrO2 revealed that the pillars are comprised of separate Zr4(μ-OH)8(OH)m (H2O)n units (Zr4 tetramers) and their dimers (Zr8 complexes) as sheets or loose 3D structures. This agrees with the results of modeling of the condensation process in solution using the Density Functional Theory approach (DFT) and the semiempirical PM3 method. Bridging and terminal hydroxyls strongly bound with Zr cations are involved in anchoring supported Cu cations and Pt. This nanostructure of the active component as well as the developed micro- and mesoporosity appear to be responsible for the high performance of Pt+Cu/ZrPILC catalysts in the NOx selective reduction by propylene and decane in realistic feeds.

A combination of quantum-chemical approaches including DFT, semiempirical PM3 and molecular mechanics (force field MM+) methods has been applied for analysis of the structure of polynuclear hydroxocomplexes of Zr in diluted solutions of its oxochloride as precursors of zirconia nanoparticles in zirconia-pillared clays. Relative stability of complexes differing by their size and shape has been estimated.

Genesis of the structure of zirconia fine particles prepared by precipitation of amorphous hydrated zirconia by ammonia from the ZrO(NO3)2 solution followed by a mild hydrothermal treatment (HTT) of precipitate, washing and calcination under air up to 1000 °C has been studied by HRTEM, X-ray diffraction, Raman and FTIRS. HTT rearranges the structure of amorphous zirconia, which helps to obtain nearly single-phase monoclinic nanozirconia (particle size 5-15 nm) after a mild calcination at 500 °C. Dehydroxilation and sintering of these nanoparticles at higher (600-650 °C) temperatures generate polysynthetic (001) twins. Modeling revealed that reappearance of the (111) “cubic” reflex in XRD patterns of samples calcined at 600-650 °C can be due to these extended defects. In their vicinity, the seven-fold Zr-O coordination sphere is retained, while packing of ZrO7 polyhedra is varied towards more symmetric structures, thus causing disappearance of the Raman spectra.

The impact of powdered oxides of Mg, Ca, La, Ti, Al or their nitrate salts on the properties of MeOx/Al2O3/Al composites obtained via the hydrothermal treatment (HTT) of Al-based blends put in a closed space of the die allowing the free water vapor access has been studied. Additives were found to affect the process of aluminum oxidation mainly through variation of the density of formed aluminum hydroxide layer. In some cases, incorporation of dopant cations into the structure of alumina formed after calcination of composite in air was revealed by 27 Al MAS NMR. Variation of the Al oxidation degree and associated change of the solid phase volume in a closed die caused by dopants affects also the pore structure and texture of composites determining the mechanical strength of produced monoliths. The processes of the redistribution of soluble additives between the solid phase and autoclave solutions were revealed and their consequences are considered.

This work presents results of studies of the structural features of nanocrystalline doped Ce1−xMexO2−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.

This work presents results of investigation of the charge and coordination state of Fe cations in La1-xMexFeO3-y perovskites prepared by mechanochemical route by using MÖssbauer spectroscopy as related to bulk oxygen reactivity in H2 or in CH4 temperature-programmed reduction (TPR).

The features of the structure of nanorystalline Ce1-xPrxO2-y system (0 ≤ × ≤ 0.5) prepared via a complex polymerized precursor (Pechini) route have been elucidated by using a combination of spectroscopic (XANES, XPS) and structural (TEM, neutron diffraction) methods. Within the studied range of composition, the structure of all samples air annealed at 500 °C corresponds to single-phase fluorite-like solid solution. The relative content of Pr3+ both in the bulk and in the surface layer appears to be as high as 20–50%. The Rietveld refinement revealed non-monotonous variation of structural parameters (lattice parameter, domain size, microstrain density, Ce-O and O-O distances) and residual lattice hydroxyls concentration with Pr content. Clustering of defects along with variation of the mean Pr cation radius/charge state and disordering of the surface layer/ domain boundaries appear to be responsible for the observed features.

This work presents the first results of synthesis of framework binary phosphates of zirconium and transition metal cations (Co, Cu, Ce) via nanocomposites of starting inorganic salts with citric acid and studies of their structure genesis. Nanoparticles of layered Zr phosphates with typical sizes in the range of 18–24 Å are formedat the mixing stage. Less basic Cu and Co cations are mainly octa-coordinated with both phosphate groups of those nanoparticles and citric acid molecules. At subsequent thermal treatment, Cu and Co cations are incorporated within Zr phosphate nanoparticles acquiring a low coordination approaching a tetrahedral one while rearranging the nuclei structure into that of a framework type. Removal of citric acid by heating under air at 200–300°C preserves the size of nanoparticles while their ordered stacking forms mesoporous structure with a narrow pore size distribution ∼ 50 Å and specific surface area up to 200 m2/g after calcination at 600°C. The binary phosphates promoted by a small amount of Pt were found to be effective catalysts of NOx selective reduction by decane in the oxygen excess not subjected to coking with a high and stable performance at high space velocities in the presence of steam.

Some perovskite –like Fe (Co) -containing and fluorite-like Bi –containing solid solutions considered as promising materials for high oxygen flux membranes application have been synthesized by the mechanochemical activation route. Structural/microstructural features of those systems characterized by TEM, XRD, IR, and Raman spectroscopy are compared with the data on their mixed conductivity and oxygen mobility. Some properties of nanocomposites comprised of those materials and such oxides as Fe2O3, BaTiO3, BaBiO3 etc are elucidated as well. Densification of those powdered samples by sintering in the 700–1400 K temperature range is accompanied by annealing of metastable phases generating “core-shell” nanocomposites with oxygen transport properties different from those of traditional materials.

Thermally stable alumina and zirconia pillared clays loaded with copper and cobalt cations and silver nanoparticles were synthesized. The structural and surface features of these nanosystems were studied and compared with those of bulk analogs -partially stabilized zirconias and γ-alumina loaded with the same active components. Specificity of the catalytic properties of nanocomposites in the reactions of nitrogen oxides reduction by propane, propylene and decane in the excess of oxygen appears to be determined both by the degree of interaction between pillars and active components and the type of reducing agent.

The structure and surface properties of composites based upon high-surface-area framework zirconium phosphates with supported WO3, MoO3 and Pt nanoparticles were studied by using combination of structural and spectral methods. The effect of these promoters on performance of zirconium phosphates in the reaction of pentane and hexane isomerization is considered.