Anatoly Bortun has 20 years academy and 15 years industry experience with background in Physical and Inorganic Chemistry. His expertise is in areas of adsorption/ion exchange, separations and materials chemistry, including hydrothermal, sol-gel and solid state syntheses.
New automotive emission standards make stringent requirements for oxygen-storage materials used in three way catalysts (TWC) and diesel catalysts. PIDC has developed an original precipitation technique for making wide range of ceria-zirconia (CZ) compositions. The key feature of the novel process is a presence of certain organic and/or inorganic additives specifically interacting with polyvalent metals in aqueous solution. The dual role of additives has been found. They change primary particles charge and surface charge density. Also, they specifically interact with Zr(Ce) species by occupying or blocking some of their active sites, which prevents dense packing of primary particles and their aggregates. This allows tailored assembly of mixed oxide structural blocks throughout all stages of precipitation with the formation of open-framework hierarchical structures. Other synthetic steps – washing precipitate from ionic admixtures, drying, calcinations, etc., are also important for retaining and fixation of hydrogel open-framework structures. Based on experimental data optimal conditions for making mixed oxides with porosity that can be controlled and regulated in a broad range from 50-10 nm up to 60-100 nm and improved thermal stability up to 1100oC have been determined. Novel CZ materials exhibit high oxygen storage capacity and improved compatibility with precious metals. Results of CZ characterization with the use of different methods: XRD, SEM, TEM, N2 adsorption, TPR-H2, etc., will be presented.
Mihai I Sturza has his expertise in synthesis and crystal structure characterization of novel inorganic compounds. The main aim of his work is to synthesize new inorganic compounds (new oxides, oxo-halides, pnictides, chalcogenides, intermetallics, etc.) and to correlate their chemical and physical properties to their compositions and crystal structures. His research at IFW involves searching for novel low-dimensional materials with interesting electronic properties emerging from a competition between different electronic states or a suppression of the electronic order (charge, orbital or spin).
The class of transition-metal chalcogenides that exhibits mixed valency has been of continuing interest for several decades. The emergence of superconductivity with a superconducting transition temperature (Tc<30 K) in mixed-valence AxFe2−ySe2 (A=K, Rb, Cs, and Tl) phases has further increased interest in the chemistry and physics of complex ternary transition-metal chalcogenides. Copper chalcogenide materials are of considerable scientific interest because of their rich structural and compositional diversity, mixed valency, propensity for phase transitions, charge-density waves, potential for ionic mobility, as well as applications such as high performance photovoltaic cells. New results from the chemistry of the A/Cu/Q (A=Na, K, Ba; Q=S, Se) system will be reported. The synthesis, crystal structure, and properties of new layered copper chalcogenide compounds, which are mixed-valent will be presented. Single crystals were grown by the reaction of Cu metal in a molten alkali/ alkaline-earth metal/polysulfide/polyselenide/flux. Single crystal x-ray diffraction measurements performed on several crystals showed a high quality of the crystals, proven by the good internal consistency of the data collected using the full-sphere mode and an extremely low R factor. Electronic band structure calculations and physical property measurements reveal p-type metallic behavior, with moderately high electrical conductivity and hole carrier mobilities.