Enhanced thermal stability of Ce0.33Zr0.55（LaNdY）0.12O2 mixed oxides prepared by sulfate-aided coprecipitation method
来源期刊：JOURNAL OF RARE EARTHS2021年第5期
论文作者：Shilei Chen Yongke Hou Hao Wang Zheng Zhao Yongqi Zhang Juanyu Yang Xiaowei Huang
摘 要：Ceria-zirconia based mixed oxides（CZs） have been applied in three-way catalysts（TWCs） for their high surface area and oxygen storage capacity（OSC）.In this work,enhanced thermal stability of Ce0.33Zr0.55（LaNdY）0.12O2 mixed oxides was realized via a facile and scalable approach,namely,sulfateaided coprecipitation method was labelled as CZ-S.Sulfate ion(SO42-) was added into raw solution in the form of sulfuric acid and acted as coordination agent.The control sample was prepared by conventional coprecipitation method without sulfuric acid added and labelled as CZ.The promotion effect of sulfate ion was analyzed systematically by X-ray diffraction（XRD）,transmission electron microscopy（TEM）,scanning electron microscopy（SEM）,N2 adsorption-desorption,Fourier transform infrared spectroscopy（FT-IR）,X-ray photoelectron spectroscopy（XPS）,OSC and hydrogen temperatureprogrammed reduction（H2-TPR） analysis.XRD and high resolution TEM results reveal that CZ-S have homogeneous distributions of elements.TEM and SEM images show that fresh samples of CZ-S have narrower distributions of grain sizes and larger pore sizes than those of CZ.Through cross analysis of structure and morphology of CZ and CZ-S,we find that the introduction of sulfate ions results in uniform distributions of elements,narrows distributions of grain sizes,and enables the formation of secondary loose packing of sub-particles,which lead to enhanced thermal stability of the samples of CZ-S upon aging process at high temperature.After aging treatment at 1100℃ for 10 h,aged samples of CZ-S present larger specific surface areas and pore volumes than the aged sample prepared by conventional coprecipitation method without sulfate ions added.Furthermore,the aged sample of CZ-S2(SO42-/Zr=1)possesses the highest specific surface area of 21.9 m2/g and the biggest pore volume of 0.035 mL/g among all aged samples.
Shilei Chen1,2，Yongke Hou1,3,2，Hao Wang1,2，Zheng Zhao1,2，Yongqi Zhang1,3,4，Juanyu Yang1,3,4，Xiaowei Huang1,2,4
1. National Engineering Research Center for Rare Earth Materials,GRINM Group Co.,Ltd.2. General Research Institute for Nonferrous Metals
摘 要：Ceria-zirconia based mixed oxides（CZs） have been applied in three-way catalysts（TWCs） for their high surface area and oxygen storage capacity（OSC）.In this work,enhanced thermal stability of Ce0.33Zr0.55（LaNdY）0.12O2 mixed oxides was realized via a facile and scalable approach,namely,sulfateaided coprecipitation method was labelled as CZ-S.Sulfate ion(SO42-) was added into raw solution in the form of sulfuric acid and acted as coordination agent.The control sample was prepared by conventional coprecipitation method without sulfuric acid added and labelled as CZ.The promotion effect of sulfate ion was analyzed systematically by X-ray diffraction（XRD）,transmission electron microscopy（TEM）,scanning electron microscopy（SEM）,N2 adsorption-desorption,Fourier transform infrared spectroscopy（FT-IR）,X-ray photoelectron spectroscopy（XPS）,OSC and hydrogen temperatureprogrammed reduction（H2-TPR） analysis.XRD and high resolution TEM results reveal that CZ-S have homogeneous distributions of elements.TEM and SEM images show that fresh samples of CZ-S have narrower distributions of grain sizes and larger pore sizes than those of CZ.Through cross analysis of structure and morphology of CZ and CZ-S,we find that the introduction of sulfate ions results in uniform distributions of elements,narrows distributions of grain sizes,and enables the formation of secondary loose packing of sub-particles,which lead to enhanced thermal stability of the samples of CZ-S upon aging process at high temperature.After aging treatment at 1100℃ for 10 h,aged samples of CZ-S present larger specific surface areas and pore volumes than the aged sample prepared by conventional coprecipitation method without sulfate ions added.Furthermore,the aged sample of CZ-S2(SO42-/Zr=1)possesses the highest specific surface area of 21.9 m2/g and the biggest pore volume of 0.035 mL/g among all aged samples.
关键词：
