Effect of grain size on thermal stability and oxygen storage capacity of Ce_(0.17)Zr_(0.73)La_(0.02)Nd_(0.04)Y_(0.04)O_2 solid solutions
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摘要
Nanostructured CeO_2-ZrO_2 materials are an irreplaceable constituent in catalytic systems for automobile exhaust purification due to their unique oxygen storage capacity(OSC). However, traditional CeO_2-ZrO_2 materials are easy to sinter at high temperature, which causes a sharp decrease of OSC. In this paper,La~(3+) , Nd~(3+) and Y~(3+) are chosen as dopants for CeO_2-ZrO_2 to improve anti-sintering and OSC properties.The Ce_(0.17) Zr_(0.73) La_(0.02) Nd_(0.04) Y_(0.04) O_2 powders(CZLNY) were prepared by co-precipitation method. The effects of grain sizes with different mixed chlorinated solution concentrations on performances were investigated. X-ray diffraction(XRD) and transmission electron micrograph(TEM) were performed to calculate the grain sizes of CZLNY. The specific surfaces, OSC and redox properties were investigated by N_2 adsorption/desorption and temperature programmed reduction(H2-TPR). The results show that introducing La~(3+) , Nd~(3+) and Y~(3+) into CeO_2-ZrO_2 lattice can improve the stability of phase structure and anti-sintering ability. Moreover, low concentration of mixed chlorinated solution remarkably improves structural and textural properties of CZLNY. Relatively large fresh grain exhibits superior thermal stability and OSC under the condition of being calcined at 800℃ for 3 h. The specific surface and OSC are42.37 m~2/g and 333.13 mmol/g after calcining at 1000℃ for 10 h, respectively. This is owing to the low sintered driving force of large grain and long-range migration energy of large pores during the sintering process, which are beneficial to the stability of structure in CZLNY materials.
Nanostructured CeO_2-ZrO_2 materials are an irreplaceable constituent in catalytic systems for automobile exhaust purification due to their unique oxygen storage capacity(OSC). However, traditional CeO_2-ZrO_2 materials are easy to sinter at high temperature, which causes a sharp decrease of OSC. In this paper,La~(3+) , Nd~(3+) and Y~(3+) are chosen as dopants for CeO_2-ZrO_2 to improve anti-sintering and OSC properties.The Ce_(0.17) Zr_(0.73) La_(0.02) Nd_(0.04) Y_(0.04) O_2 powders(CZLNY) were prepared by co-precipitation method. The effects of grain sizes with different mixed chlorinated solution concentrations on performances were investigated. X-ray diffraction(XRD) and transmission electron micrograph(TEM) were performed to calculate the grain sizes of CZLNY. The specific surfaces, OSC and redox properties were investigated by N_2 adsorption/desorption and temperature programmed reduction(H2-TPR). The results show that introducing La~(3+) , Nd~(3+) and Y~(3+) into CeO_2-ZrO_2 lattice can improve the stability of phase structure and anti-sintering ability. Moreover, low concentration of mixed chlorinated solution remarkably improves structural and textural properties of CZLNY. Relatively large fresh grain exhibits superior thermal stability and OSC under the condition of being calcined at 800℃ for 3 h. The specific surface and OSC are42.37 m~2/g and 333.13 mmol/g after calcining at 1000℃ for 10 h, respectively. This is owing to the low sintered driving force of large grain and long-range migration energy of large pores during the sintering process, which are beneficial to the stability of structure in CZLNY materials.
Nanostructured CeO_2-ZrO_2 materials are an irreplaceable constituent in catalytic systems for automobile exhaust purification due to their unique oxygen storage capacity(OSC). However, traditional CeO_2-ZrO_2 materials are easy to sinter at high temperature, which causes a sharp decrease of OSC. In this paper,La~(3+) , Nd~(3+) and Y~(3+) are chosen as dopants for CeO_2-ZrO_2 to improve anti-sintering and OSC properties.The Ce_(0.17) Zr_(0.73) La_(0.02) Nd_(0.04) Y_(0.04) O_2 powders(CZLNY) were prepared by co-precipitation method. The effects of grain sizes with different mixed chlorinated solution concentrations on performances were investigated. X-ray diffraction(XRD) and transmission electron micrograph(TEM) were performed to calculate the grain sizes of CZLNY. The specific surfaces, OSC and redox properties were investigated by N_2 adsorption/desorption and temperature programmed reduction(H2-TPR). The results show that introducing La~(3+) , Nd~(3+) and Y~(3+) into CeO_2-ZrO_2 lattice can improve the stability of phase structure and anti-sintering ability. Moreover, low concentration of mixed chlorinated solution remarkably improves structural and textural properties of CZLNY. Relatively large fresh grain exhibits superior thermal stability and OSC under the condition of being calcined at 800℃ for 3 h. The specific surface and OSC are42.37 m~2/g and 333.13 mmol/g after calcining at 1000℃ for 10 h, respectively. This is owing to the low sintered driving force of large grain and long-range migration energy of large pores during the sintering process, which are beneficial to the stability of structure in CZLNY materials.
引文
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17.Chen A,Zhou Y,Ta N,Li Y,Shen WJ.Redox properties and catalytic performance of ceria-zirconia nanorods.Catal Sci Technol.2015;5:4184.
18.Li XZ,Ni CY,Chen F,Lu XW,Chen ZG.Mesoporous mesocrystal Ce1àxZrxO2with enhanced catalytic property for CO conversion.J Solid State Chem.2009;182:2185.
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20.Bochechka AA.The analysis of the motive forces of sintering micro-and nanosized diamond powders at high pressure.J Superhard Mater.2009;31:292.
21.Cui YJ,Lan L,Shi ZH,Yuan SD,Gong MC,Chen YQ,et al.Effect of surface tension on the properties of a doped CeO2-ZrO2composite and its application in a Pdonly three-way catalyst.RSC Adv.2016;6:66524.
22.Wang QY,Li GF,Zhao B,Zhou RX.Synthesis of La modified Ceriaezirconia solid solution by advanced supercritical ethanol drying technology and its application in Pd-only three-way catalyst.Appl Catal B Environ.2010;100:516.
23.Kaspar J,Monte RD,Fornasiero P,Graziani M,Bradshaw H,Norman C.Dependency of the oxygen storage capacity in zirconia-ceria solid solutions upon textural properties.Top Catal.2001;16:83.
24.Li GF,Wang QY,Zhao B,Zhou RX.Promoting effect of synthesis method on the property of nickel oxide doped CeO2-ZrO2and the catalytic behaviour of Pdonly three-way catalyst.Appl Catal B Environ.2011;105:151.
25.Vlaic G,Fornasiero P,Geremia S,Kaspar Graziani M.Relationship between the zirconia-promoted reduction in the Rh-loaded Ce0.5Zr0.5O2mixed oxide and the Zr-O local structure.J Catal.1997;168:386.
2.Wang QY,Zhao B,Li GF,Zhou RX.Application of rare earth modified Zr-based ceria-zirconia solid solution in three-way catalyst for automotive emission control.Environ Sci Technol.2010;44:3870.
3.Matsumoto S.Recent advances in automobile exhaust catalyst.Catal Surv Asia.1997;1:111.
4.Li L,Chen SH,Cao Y,Zhao M,Gong MC,Chen YQ.Preparation of ceria-zirconia by modified coprecipitation method and its supported Pd-only three-way catalyst.J Colloid Interface Sci.2015;450:404.
5.Andriopoulou C,Trimpalis A,Petallidou KC,Sgoura A.Structural and Redox properties of Ce1exZrxO2àdand Ce0.8Zr0.15RE0.05O2àd(RE:La,Nd,Pr,Y)solids studied by high temperature in situ Raman spectroscopy.J Phys Chem C.2017;121:7931.
6.Wang G,Meng M,Zha YQ,Ding T.High-temperature close coupled catalysts Pd/Ce-Zr-M/Al2O3(M?Y,Ca or Ba)used for the total oxidation of propane.Fuel.2010;89:2244.
7.Chen JJ,Hu W,Huang FJ,Li GX,Yuan SD,Chen YQ.Catalytic performance of a Pt-Rh/CeO2-ZrO2-La2O3-Nd2O3three-way compress nature gas catalyst prepared by a modified double-solvent method.J Rare Earths.2017;35(9):857.
8.Li GF,Wang QY,Zhao B,Zhou RX.The promotional effect of transition metals on the catalytic behavior of model Pd/Ce0.67Zr0.33O2 three-way catalyst.Catal Today.2010;385:392.
9.Wang QY,Li GF,Zhao B,Shen MQ,Zhou RX.The effect of La doping on the structure of Ce0.2Zr0.8O2and the catalytic performance of its supported Pd-only three-way catalyst.Appl Catal B Environ.2010;101:150.
10.Wang QY,Li GF,Zhao B,Zhou RX.The effect of Nd on the properties of CeriaZirconia solid solution and the catalytic performance of its supported Pd-only three-way catalyst for gasoline engine exhaust reduction.J Hazard Mater.2011;189:150.
11.Dong F,Tanabe T,Suda A,Takahashi N,Sobukawa H,Shinjoh H.Investigation of the OSC performance of Pt/CeO2-ZrO2-Y2O3catalysts by CO oxidation and18O/16O isotopic exchange reaction.Chem Eng Sci.2008;63:5020.
12.Ifrah ES,Rohart J,Hernandez.Composition containing oxides of zirconium,cerium and another rare earth having reduced maximum reducibility temperature,a process for preparation and use thereof in the field of catalysis.US Patent:US 2013/0052108 A1.
13.Ifrah SE,Rohart J,Hernandez.Composition based on oxides of cerium,of zirconium and of another rare earth metal with high reducibility,preparation process and use in the field of catalysis.US Patent:US 2014/0205522 A1.
14.Gupta A,Waghmare UV,Hegde MS.Correlation of oxygen storage capacity and structural distortion in transition-metal-,noble-metal-,and rare-earth-ionsubstituted CeO2from first principles calculation.Chem Mater.2010;22:5184.
15.Zhou Y,Deng J,Xiong L,Wang JL,Yuan SD,Chen YQ,et al.Synthesis and study of nanostructured Ce-Zr-La-RE-O(RE?Y,Nd and Pr)quaternary solid solutions and their supported three-way catalysts.Mater Des.2017;130:149.
16.Li M,Liu ZG,Hu YH,Wang MT,Li HQ.Effect of doping elements on catalytic performance of CeO2-ZrO2solid solutions.J Rare Earths.2008;26:357.
17.Chen A,Zhou Y,Ta N,Li Y,Shen WJ.Redox properties and catalytic performance of ceria-zirconia nanorods.Catal Sci Technol.2015;5:4184.
18.Li XZ,Ni CY,Chen F,Lu XW,Chen ZG.Mesoporous mesocrystal Ce1àxZrxO2with enhanced catalytic property for CO conversion.J Solid State Chem.2009;182:2185.
19.Verma R,Samdarshi SK,Bojja S,Paul S,Choudhury B.A novel thermophotocatalyst of mixed-phase cerium oxide(CeO2/Ce2O3)homocomposite nanostructure:role of interface and oxygen vacancies.Sol Energ Mat Sol C.2015;141:414.
20.Bochechka AA.The analysis of the motive forces of sintering micro-and nanosized diamond powders at high pressure.J Superhard Mater.2009;31:292.
21.Cui YJ,Lan L,Shi ZH,Yuan SD,Gong MC,Chen YQ,et al.Effect of surface tension on the properties of a doped CeO2-ZrO2composite and its application in a Pdonly three-way catalyst.RSC Adv.2016;6:66524.
22.Wang QY,Li GF,Zhao B,Zhou RX.Synthesis of La modified Ceriaezirconia solid solution by advanced supercritical ethanol drying technology and its application in Pd-only three-way catalyst.Appl Catal B Environ.2010;100:516.
23.Kaspar J,Monte RD,Fornasiero P,Graziani M,Bradshaw H,Norman C.Dependency of the oxygen storage capacity in zirconia-ceria solid solutions upon textural properties.Top Catal.2001;16:83.
24.Li GF,Wang QY,Zhao B,Zhou RX.Promoting effect of synthesis method on the property of nickel oxide doped CeO2-ZrO2and the catalytic behaviour of Pdonly three-way catalyst.Appl Catal B Environ.2011;105:151.
25.Vlaic G,Fornasiero P,Geremia S,Kaspar Graziani M.Relationship between the zirconia-promoted reduction in the Rh-loaded Ce0.5Zr0.5O2mixed oxide and the Zr-O local structure.J Catal.1997;168:386.