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Effect of Zirconium Precursor on Performance of Pd/Ce0.45Zr0.45La0.1O1.95 Three-Way Catalyst

陈山虎 , 姚艳玲 , 兰丽 , 曹毅 , 闫朝阳 , 龚茂初 , 陈耀强

催化学报 doi:10.1016/S1872-2067(11)60445-2

Three types of Ce0.45Zr0.45La0.1O1.95 mixed oxides were prepared by H2O2-assisted precipitation using ZrOCO3, ZrO(NO3)2, and Zr(NO3)4 as precursors. The Pd/Ce0.45Zr0.45La0.1O1.95 three-way catalysts were prepared by the wet impregnation and characterized by the X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), and oxygen storage capacity. XRD and Raman spectroscopy results showed that the use of ZrOCO3 or ZrO(NO3)2 gave a CeO2-ZrO2 mixed oxide with a cubic phase of high thermal stability, while an extra t″-phase was observed in the aged Pd/Ce0.45Zr0.45La0.1O1.95 catalyst prepared using Zr(NO3)4. The activities of the three catalysts were evaluated using simulated exhaust gas under working conditions. The Pd/Ce0.45Zr0.45La0.1O1.95 catalyst prepared using ZrOCO3 as precursor gave the best activities for C3H8, CO, and NO conversion. The use of ZrOCO3 as precursor was better suited for the formation of Ce3+and more favorable for the homogeneous insertion of Zr4+ and La3+ into the CeO2 lattice, which resulted in better thermal stability and enhanced redox properties of the Pd/Ce0.45Zr0.45La0.1O1.95 catalyst.

关键词: oxygen storage material , oxidation-coprecipitation , thermal stability , redox property , three-way activity

高性能Ce0.5Zr0.5O2稀土储氧材料的制备及其负载的单Pd三效催化剂

闫朝阳 , 兰丽 , 陈山虎 , 赵明 , 龚茂初 , 陈耀强

催化学报 doi:10.3724/SP.J.1088.2012.10933

以碳酸铵水溶液为沉淀剂,改变前驱体盐溶液的浓度,采用共沉淀法制得了一系列Ce0.5Zr0.5O2固溶体材料.以此系列材料为载体制备了负载型单Pd三效催化剂,并利用N2吸附-脱附、X射线衍射、储氧量测定和程序升温还原等技术对材料了进行表征.结果表明,所制Ce0.5Zr0.5O2材料具有优异的抗高温老化性能和氧化还原性能,且盐溶液的浓度对材料及其负载型Pd三效催化剂性能的影响较大.当盐溶液浓度为0.3 mol/L时,制备材料的织构性能最佳,经1000℃老化5h后其比表面积和孔体积分别为53.0 m2/g和0.17 cm3/g.所制得的三效催化剂对CO,NO和C3H8具有低的起燃温度和完全转化温度,表现出最佳的催化性能,具有良好的应用前景.

关键词: 铈-锆固溶体共沉淀 , 碳酸铵 , 高温稳定性 , 氧化还原性能 , , 三效催化剂

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