Effects of precursor moisture and inert N2 atmosphere calcinations on structure and properties of alumina modified CeZrLaNd mixed oxides
来源期刊：JOURNAL OF RARE EARTHS2019年第6期
论文作者：Meisheng Cui Zhizhe Zhai Hao Wang Yongke Hou Yongqi Zhang Xiaowei Huang
文章页码：609 - 616
摘 要：CeO2-ZrO2 mixed oxides are widely used in the three-way catalysts due to their unique reversible oxygen storage and release capacity. Large surface area, high oxygen storage capacity and good thermal stability of cerium zirconium mixed oxides are the key properties for the automotive catalysts so as to meet the strict emission regulations. In this work, alumina modified CeZrLaNd mixed oxides were prepared by a co-precipitation method. The effects of moisture in precursor and inert N2 atmosphere during calcinations on the structure and properties were investigated by Brunauer-Emmett-Teller（BET） surface area measurements, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, hydrogen temperature-programmed reduction（H2-TPR）, oxygen storage capacity（OSC）, Raman spectroscopy, and X-ray photoelectron spectroscopy（XPS）. The results show that the moisture in precursor during calcinations increases the crystal grain size of the cerium zirconium mixed oxides, improving the thermal stability. And the aged surface area of sample after being calcined at1000 ℃ for 4 h reaches 68.8 m2/g（5.7% increase compared with the common sample）. The inert N2 atmosphere endows a great pore-enlarging effect, which leads to high fresh surface area of 148.9 m2/g（13.5% increase compared with the common sample） and big pore volume of 0.5705 mL/g. The redox and oxygen storage capacity are also improved by inert N2 atmosphere with high OSC value of 241.06μmolO2/g（41.3% increase compared with the common calcination）, due to the abundant formation of the crystal defects and oxygen vacancies.
Meisheng Cui1,2，Zhizhe Zhai1，Hao Wang1，Yongke Hou1,2，Yongqi Zhang1,2，Xiaowei Huang1,2
1. National Engineering Research Center for Rare Earth Materials,General Research Institute for Nonferrous Metals2. Grirem Advanced Materials Co.,Ltd.
摘 要：CeO2-ZrO2 mixed oxides are widely used in the three-way catalysts due to their unique reversible oxygen storage and release capacity. Large surface area, high oxygen storage capacity and good thermal stability of cerium zirconium mixed oxides are the key properties for the automotive catalysts so as to meet the strict emission regulations. In this work, alumina modified CeZrLaNd mixed oxides were prepared by a co-precipitation method. The effects of moisture in precursor and inert N2 atmosphere during calcinations on the structure and properties were investigated by Brunauer-Emmett-Teller（BET） surface area measurements, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, hydrogen temperature-programmed reduction（H2-TPR）, oxygen storage capacity（OSC）, Raman spectroscopy, and X-ray photoelectron spectroscopy（XPS）. The results show that the moisture in precursor during calcinations increases the crystal grain size of the cerium zirconium mixed oxides, improving the thermal stability. And the aged surface area of sample after being calcined at1000 ℃ for 4 h reaches 68.8 m2/g（5.7% increase compared with the common sample）. The inert N2 atmosphere endows a great pore-enlarging effect, which leads to high fresh surface area of 148.9 m2/g（13.5% increase compared with the common sample） and big pore volume of 0.5705 mL/g. The redox and oxygen storage capacity are also improved by inert N2 atmosphere with high OSC value of 241.06μmolO2/g（41.3% increase compared with the common calcination）, due to the abundant formation of the crystal defects and oxygen vacancies.
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