Nanocrystalline Doped Ceria-Zirconia Fluorite-Like Solid Solutions Promoted by Pt: Structure, Surface Properties and Cat
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0988-QQ06-04
Nanocrystalline Doped Ceria-Zirconia Fluorite-Like Solid Solutions Promoted by Pt: Structure, Surface Properties and Catalytic Performance in Syngas Generation Vladislav A. Sadykov1, Natalia Mezentseva1, Galina Alikina1, Anton Lukashevich1, Vitalii Muzykantov1, Tatiana Kuznetsova1, Lubsan Batuev1, Martin Fedotov1, Ella Moroz1, Dmitrii Zyuzin1, Vera Kolko1, Vladimir Kriventsov1, Vyacheslav Ivanov1, Andrei Boronin1, Egor Pazhetnov1, Vladimir Zaikovskii1, Arcady Ishchenko1, Vladimir Rogov1, Julian Ross2, and Erhard Kemnitz3 1 Heterogeneous catalysis, Boreskov Institute of Catalysis, pr. Lavrentieva, 5, Novosibirsk, 630090, Russian Federation 2 University of Limerick, Limerick, Ireland 3 Humboldt University, Berlin, D-12489, Germany
ABSTRACT 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. INTRODUCTION Ceria-zirconia oxide solid solutions with supported precious metals are promising for such applications as automotive catalysis [1], transformation of hydrocarbons or oxygenates into syngas by partial oxidation or autothermal reforming [2,3], solid oxide fuel cells anodes [4] etc. For these applications, the lattice oxygen mobility is an important factor ensuring a high efficiency and stable performance of these systems. The incorporation of rare earth cations with lower (La3+, Sm3+, Gd3+) or variable (Pr3+/4+) charges into Ce-Zr-O is expected to stabilize their structure and increase the oxygen mobility due to formation of oxygen vacancies [1], though there is still a lack of systematic research in this area. This work aims at elucidating the effect of the type and content of a doping cation (mainly, Gd, Pr) on the real structure, surface properties and oxygen mobility of nanocrystalline ceria-zirconia solid solutions prepared by modified Pechini route as related to catalysis of syngas generation by autothermal reforming of acetone at short contact times. EXPERIMENT Dispersed samples of ceria-zirconia (1:1)-based solid solutions with La, Pr, Gd or Sm content in the range of 5–30 at.% were prepared by a polymerized complex precursor route and calcined at 500-700 oC for 4 h [2, 5]. Pt (1.4 wt.%) was supported from H2PtCl6 solution by incipient wetness impregnation followed by drying and calcination at 500 oC for 2 h.
Structural features of samples were characterized by X-ray Diffraction (XRD), Extended Xray Absorption Fine Structure Spectroscopy (EXAFS), Wide-Angle X-ray Scattering (WAXS) and UV-Vis Spectroscopy. XRD patterns were obtained with an URD-6 diffractometer
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