Intergrowth Effects in CeO2-Y-Al2O3 Mixed Oxides

An improved amorphous citric precursor method was used to synthesize Ce-Al-O mixed oxides. The samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, 27Al magic angle spinning nuclear magnetic resonance, N2 adsorption, and oxygen storage capacity (OSC) measurement. There was a strong intergrowth interaction between CeO2 and γ-Al2O3 oxide crystallites during the synthesis, which influenced the microstructure and crystal growth of the two coexisting oxides and resulted in a high hydrothermal stability for γ-Al2O3. The OSC per unit mass of the Ce-Al-O system was 2–3 times higher than that of a single phase CeO2 with a nanocrystalline structure even after hydrothermal treatment at a high temperature. With a mechanical mixture, this improved OSC was not observed because there was no oxide crystallite intergrowth.

摘要：采用改进的柠檬酸络合法合成了 Ce-Al-O 两相氧化物, 并运用 X 射线衍射、X 射线光电子能谱、27Al 魔角核磁、N2 吸附-脱附和储氧量测定等手段对样品进行了表征. 结果表明, 两相共生时 CeO2 和 γ-Al2O3 间发生了强相互作用, 相互调变了彼此的存在状态和微观结构, 抑制了两物相晶粒的长大, 从而提高了 γ-Al2O3 的高温水热老化稳定性, 并使 Ce-Al-O 体系两相氧化物的储氧能力比单相的纳米 CeO2 提高了 2∼3 倍, 即使在高温水热处理后样品仍保持很高的储氧性能. 

The biphasic intergrowth of CeO2 and γ-Al2O3 oxides showed a strong interaction between the two oxides. They showed a highly enhanced oxygen storage capacity (OSC) with a plateau at 973 K.Figure optionsDownload as PowerPoint slide