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Effects of co-precipitation temperature on structure and properties of La and Y doped cerium zirconium mixed oxides 被引量:2
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作者 Lian-jie ZHANG Mei-sheng CUI +5 位作者 Hao WANG Yong-ke HOU Shi-lei CHEN Zhi-zhe ZHAI Zhi-qi LONG Yong-qi ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第2期618-628,共11页
Due to the oxygen storage and release properties,cerium zirconium mixed oxides are recognized as the key material in automotive three-way catalysts.To reveal the effects of co-precipitation temperature on structure,ph... Due to the oxygen storage and release properties,cerium zirconium mixed oxides are recognized as the key material in automotive three-way catalysts.To reveal the effects of co-precipitation temperature on structure,physical and chemical properties of multi-doped cerium zirconium mixed oxides,a series of La and Y doped cerium zirconium mixed oxides(CZLYs)were synthesized via a co-precipitation method,and the physical and chemical properties of CZLYs were systemically characterized by XRD,N_(2) adsorption−desorption,TEM,XPS,oxygen storage capacity(OSC)and hydrogen temperature programmed reduction(H_(2)-TPR).The results show that co-precipitation temperature is an important parameter to influence the crystal size,oxygen storage capacity and thermal stability of CZLYs.When the co-precipitation temperature was 60℃,the best redox properties and thermal stability of CZLYs were obtained.After thermal treatment at 1100℃for 10 h,the specific surface area and oxygen storage capacity of the corresponding aged sample were 15.42 m^(2)/g and 497.7μmol/g,respectively.In addition,a mechanism was proposed to reveal the effects of co-precipitation temperature on the structure and properties of CZLYs. 展开更多
关键词 La and Y doping cerium zirconium mixed oxides co-precipitation temperature crystal size thermal stability
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Structure and properties of cerium zirconium mixed oxide prepared under different precipitate aging processes 被引量:5
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作者 王琦 岳梅 +7 位作者 钟强 崔梅生 黄小卫 侯永可 王磊 杨宇轩 龙志奇 冯宗玉 《Journal of Rare Earths》 SCIE EI CAS CSCD 2016年第7期695-703,共9页
Oriented attachment and Ostwald ripening are two aging mechanisms of precipitation particles which may result in differ- ent crystallization mechanism of precipitates during the aging process. In this work, the effect... Oriented attachment and Ostwald ripening are two aging mechanisms of precipitation particles which may result in differ- ent crystallization mechanism of precipitates during the aging process. In this work, the effects of different aging process on the structure and properties of cerium zirconium mixed oxides were investigated. The results indicated that the mixed structure of 11.48% CeO2 phase and 88.52% Ce0.26Zr0.62(LaPr)0.1202 solid solution phase were obtained under oriented attachment aging process. The rod-like CeO2 phase coexisted with spherical Ce0.26Zr0.62(LaPr)0.1202 solid solution phase, which improved the surface area (64 m2/g) and pore volume (0.32 mL/g) of cerium zirconium mixed oxides after 1000 ℃ 4 h thermal treatment. However, through controlling the aging process, the Ce0.35Zr0.55(LaPr)0.1002 solid solution with homogenous phase structure was generated by Ostwald ripening ag- ing process, exhibiting higher oxygen storage capacity (501 μmol O2/g) and H2 consumption per gram (1378.3 μmol H2/g). 展开更多
关键词 cerium zirconium mixed oxides Ostwald ripening oriented attachment CO-PRECIPITATION rare earths
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Characterization of CeO_2-ZrO_2 mixed oxides prepared by two different co-precipitation methods 被引量:6
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作者 岳梅 崔梅生 +2 位作者 张娜 龙志奇 黄小卫 《Journal of Rare Earths》 SCIE EI CAS CSCD 2013年第3期251-256,共6页
A series of cerium zirconium mixed oxides were prepared by two co-precipitation methods using magnesium hydrogen carbonate (MHC) and mixed ammonia-ammonia hydrogen carbonate (AAHC) as precipitant respectively. The... A series of cerium zirconium mixed oxides were prepared by two co-precipitation methods using magnesium hydrogen carbonate (MHC) and mixed ammonia-ammonia hydrogen carbonate (AAHC) as precipitant respectively. The crystal structure, BET surface area and morphology of the produced cerium zirconium mixed oxides were characterized by X-ray diffraction (XRD), Bru- mauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) techniques. The reduction-oxidation behavior and oxygen storage capacity (OSC) performance were also studied by temperature programmed reduction (TPR) and oxygen pulse chemical adsorption methods. The XRD results demonstrated that the cerium zirconium mixed oxides obtained by both methods possessed struc ture of cubic solid solution phase. The fresh surface area calcinated at 600 ℃, aged surface area after 1000 ℃and OSC at 500 ℃ of cerium zirconium mixed oxides were determined to be 89.337, 34.784 ma/g, and 567 pmol O2/g for MHC method and 122.010, 46.307 m2/g, and 665 pmol O2/g for AAHC method, respectively. 展开更多
关键词 cerium zirconium mixed oxide magnesium hydrogen carbonate mixed ammonia-ammonia hydrogen carbonate co-pre-cipitation rare earths
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The effect of hydrogen peroxide on properties of Ce0.35Zr0.55La0.055Pr0.045O2 oxides and the catalytic performance usedon Pd supported three-way catalyst 被引量:5
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作者 Qi wang Meisheng Cui +4 位作者 Xiaowei Huang Yongke Hou Mei Yue Qiang Zhong YongqiZhang 《Journal of Rare Earths》 SCIE EI CAS CSCD 2017年第11期1092-1101,共10页
In this study,two series of cerium zirconium mixed oxides CeZrLaPrOwere prepared under traditional co-precipitation and oxidation co-precipitation methods respectively. The physicochemical properties of the samples we... In this study,two series of cerium zirconium mixed oxides CeZrLaPrOwere prepared under traditional co-precipitation and oxidation co-precipitation methods respectively. The physicochemical properties of the samples were compared under these two methods and assessed by XRD,Raman,BET,TEM,HTPR,OSC,XPS and catalysts measurements. The formation of homogeneity phase structure can be facilitated by changing the precipitating properties of Ce3+ under oxidation coprecipitation method, which is helpful to enhance the homogeneity of Ce and Zr at atomic level.What’s more, it is conducive to remove impurities Na~+ and Cl~-by oxidation co-precipitation with hydrogen peroxide. The catalysts activities are related to both the redox properties and the textural properties of mixed oxides. The Pd-only TWCs supported on the CZLP-H-F exhibits better catalytic performance and thermal stability with wider air/fuel ratio operation window, lower light-off and full conversion temperatures of CHand NO. The homogeneity of phase structure for cerium zirconium mixed oxide can be predicted and deduced from detecting the atomic distribution uniformity of its precursor. So this work not only provides insights into the mechanisms for phase segregation of cerium zirconium mixed oxide, but also provides a guidance to improve homogeneity of cerium zirconium mixed oxide by adding additives. 展开更多
关键词 cerium zirconium mixed oxides CO-PRECIPITATION Hydrogen peroxide Catalytic performance
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