Key Laboratory for Green Chemical Technology of State Education Ministry, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China.
J Environ Sci (China). 2012;24(4):757-64. doi: 10.1016/s1001-0742(11)60816-4.
FeOx-CeO2 mixed oxides with increasing Fe/(Ce+Fe) atomic ratio (1-20 mol%) were prepared by sol-gel method and characterized by X-ray powder diffraction (XRD), Brunauer-Emmett-Teller (BET) and Hydrogen temperature-programmed reduction (H2-TPR) techniques. The dynamic oxygen storage capacity (DOSC) was investigated by mass spectrometry with CO/O2 transient pulses. The powder XRD data following Rietveld refinement revealed that the solubility limit of iron oxides in the CeO2 was 5 mol% based on Fe/(Ce+Fe). The lattice parameters experienced a decrease followed by an increase due to the influence of the maximum solubility limit of iron oxides in the CeO2. TPR analysis revealed that Fe introduction into ceria strongly modified the textual and structural properties, which influenced the oxygen handling properties. DOSC results revealed that Ce-based materials containing Fe oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicated that the calculated apparent kinetic parameters obey the compensation effect. The three-way catalytic performance for Pd-only catalysts based on the Fe doping support exhibited the redundant iron species separated out of the CeO2 and interacted with the ceria and Pd species on the surface, which seriously influenced the catalytic properties, especially after hydrothermal aging treatment.
采用溶胶-凝胶法制备了 Fe/(Ce+Fe)原子比（1-20mol%）逐渐增加的 FeOx-CeO2 混合氧化物，并通过 X 射线粉末衍射（XRD）、BET 和氢气程序升温还原（H2-TPR）技术对其进行了表征。采用 CO/O2 瞬态脉冲的质谱法研究了动态储氧能力（DOSC）。经过 Rietveld 精修的粉末 XRD 数据表明，基于 Fe/(Ce+Fe)，氧化铁在 CeO2 中的溶解度极限为 5mol%。晶格参数由于 FeOx 在 CeO2 中的最大溶解度极限的影响而先减小后增大。TPR 分析表明，Fe 的引入强烈改变了 CeO2 的结构和表面性质，从而影响了其氧处理性能。DOSC 结果表明，具有多种价态的 Fe 氧化物的 Ce 基材料有助于大部分 DOSC。动力学分析表明，计算出的表观动力学参数符合补偿效应。基于 Fe 掺杂载体的 Pd 单催化剂的三效催化性能表明，多余的铁物种从 CeO2 中分离出来并与表面的 CeO2 和 Pd 物种相互作用，严重影响了催化性能，特别是在水热老化处理后。
