Institute of Chemistry, Humboldt Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany.
J Am Chem Soc. 2010 Feb 24;132(7):2345-9. doi: 10.1021/ja910574h.
The effect of the suppport on oxidative dehydrogenation activity for vanadia/ceria systems is examined for the oxidation of methanol to formaldehyde by use of well-defined VO(x)/CeO(2)(111) model catalysts. Temperature-programmed desorption at low vanadia loadings revealed reactivity at much lower temperature (370 K) as compared to pure ceria and vanadia on inert supports such as silica. Density functional theory is applied and the energies of hydrogenation and oxygen vacancy formation also predict an enhanced reactivity of the vanadia/ceria system. At the origin of this support effect is the ability of ceria to stabilize reduced states by accommodating electrons in localized f-states.
采用具有明确结构的 VO(x)/CeO(2)(111)模型催化剂，考察了载体对氧化铈负载氧化钒体系氧化甲醇制甲醛的氧化脱氢活性的影响。在低氧化钒负载量下进行的程序升温脱附表明，与纯氧化铈和氧化硅等惰性载体上的氧化钒相比，反应在低得多的温度（370 K）下进行。应用密度泛函理论，对氢化和氧空位形成的能量进行了计算，结果也表明氧化铈/氧化钒体系具有增强的反应活性。这种载体效应的根源在于氧化铈通过容纳局部 f 态的电子来稳定还原态的能力。
