Enhanced Reducibility of Ce1-xTixO2 Compared to That of CeO2 and Higher Redox Catalytic Activity of Ce1-x-yTixPtyO2-δ Compared to That of Ce1-xPtxO2-δ

摘要: Nanocrystalline Ce1-xTixO2 (0 ≤ x 0.4) and Ce1-x-yTixPtyO2-δ (x = 0.15, y 0.01, 0.02) solid solutions crystallizing in fluorite structure have been prepared by a single step solution combustion method. Temperature programmed reduction XPS study of 0.0−04) show complete Ti4+ to Ti3+ ∼20% Ce4+ Ce3+ state compared 8% the case pure CeO2 below 675 °C. The substitution Ti ions enhances reducibility CeO2. Ce0.84Ti0.15Pt0.01O2-δ crystallizes Pt is ionically substituted with 2+ 4+ oxidation states. H/Pt atomic ratio at 30 °C over 5 that Ce0.99Pt0.01O2-δ 4 against just 0.078 for 8 nm metal particles. Carbon monoxide hydrocarbon activity are much higher Ce1-x-yTixPtyO2 Ce1-xPtxO2 0.02). Synergistic involvement Pt2+/Pt° Ti4+/Ti3+ redox couples addition Ce4+/Ce3+ due t...