The catalytic activity of the nanosized solid solutions М0,1Zr0,18Ce0,72O2, wherein M – rare-earth metal in the oxidation reaction of carbon monoxide

The solid solutions M0,1Zr0,18Ce0,72O2, where M is a rare earth metal (REM) are synthesized. The structural and textural characteristics of prepared compositions were studied by XRD, Raman spectroscopy, TEM and low-temperature nitrogen adsorption. It is shown that the introduction of 10 mol.% REM in the solid solution Zr0,2Ce0,8O2 allows to save the cubic fluorite structure. In this case the parameter of lattice of solid solution decreases with increasing the atomic number of REM. The synthesized samples are nanosized: the ceria crystallite size is 13,3 nm, Zr0,2Ce0,8O2 – 11,2 nm, M0,1Zr0,18Ce0,72O2 – about 8 nm. According to TEM, the average particle size is 15 nm. The incorporation of REM increases the specific surface area and porosity due to the formation of more defective structure. There is determination of the catalytic activity of the synthesized solid solutions in CO oxidation in a flow reactor under the conditions: pressure 0,1 MPa, temperature of 20–500 °C, space velocity of 1800 h–1 gas mixture (vol.%): CO – 3,6; O2 – 8,0; N2 – balance. The samples with light REM (praseodymium, samarium, neodymium) were the most active, they have a high oxygen storage capacity (OSC). That new catalysts have an interest for the purification processes from gas emissions of motor vehicles.

1. Hideki Abe. Current status and future of the car exhaust catalyst // Science & Technology Trends — Quarterly Review. 2011. № 39. Р. 21—30.

2. Gandhi H.S., Graham G.W., McCabe R.W. Automotive exhaust catalysis // Journal of Catalysis. 2003. Vol. 216. Р. 433—442.

3. Matsumoto S. Recent advances in automobile exhaust catalysts // Catal. Today. 2004. Vol. 90. Р. 183—190.

4. Hori C.E., Permana H., Simon Ng.K.Y., Brenner A.B., More K., Rahmoeller K.M., Belton D. Thermal stability of oxygen storage properties in a mixed CeO2-ZrO2 system// Appl. Catal.. B. 1998. Vol. 16. Р. 105—117.

5. Christou, S.Y., Bradshaw H., Butler C., Darab J., Efstathiou A.M. Effect of thermal aging on the transient

6. kinetics of oxygen storage and release of commercial of CexZr1–xO2-based solids // Topic Catal. 2009. Vol. 52. Р. 2013—2018.

7. Boaro M., Leitenburg C., Dolcetti G., Trovarelli A. The dynamic of oxygen stroage in ceria-zirconia model catalysts measured by CO oxidation under stationary and cycling feedstream composition // J. Catal. 2000. Vol. 193. Р. 338— 347.

8. Yi Liu, Cun Wen, Yun Guo, Guanzhong Lu, Yanqin Wang. Effects of surface area and oxygen vacancies on ceria in CO oxidation: Differences and relationships // Journal of Molecular Catalysis A: Chemical. 2010. Vol. 316. Р. 59—64.

9. Иванова А.И. Физико-химические и каталитические свойства систем на основе CeO2 // Кинетика и катализ. 2009. Т. 50. № 6. С. 831—849.

10. Кузнецова Т.Г., Садыков В.А. Особенности дефектной структуры метастабильных нанодисперсных диоксидов церия и циркония и материалов на их основе // Кинетика и катализ. 2008. Т. 49. № 6. C. 886—905.

11. Skorodumova N.V., Simak S.I., Lundqvist B.I., Abrikosov I.A., Johansson B. Quantum Origin of the Oxygen Storage Capability of Ceria // Physical Review Letters. 2002. Vol. 89. № 16. id. 166601.

12. Hu Yucai, Yin Ping, Liang Tao, Jiang Wei, Liu Bing. Rare Earth Doping Effects on Properties of Ceria-Zirconia Solid Solution // Journal of Rare Earths. 2006. Vol. 24. Р. 86—89.

13. Li Mei, Lio Zhaogang, Hu Yanhong, Wang Mitang, Li Hangquan. Effect of doping elements on catalytic performance of CeO2-ZrO2 solid solutions // Journal of Rare Earths. 2008. Vol. 26. Р. 357—361.

14. Mikulova J., Rossignol S., Gerardy F., Mesnard D., Kappenstein C., Duprez D. Properties of cerium—zirconium mixed oxides partially substituted by neodymium: Comparison with Zr—Ce—Pr—O ternary oxides // J. Solid State Chemistry. 2006. Vol. 179. Р. 2511—2520.

15. Zhenjin K., Zhenchuan K. Quaternary Oxide of Cerium, Terbium, Praseodymium and Zirconium for Three-Way Catalysts // Journal of Rare Earths. 2006. Vol. 24. Р. 314— 319.

16. Lei Cao, Changjun Ni, Zhongshan Yuan, Shudong Wang. Correlation between catalytic selectivity and oxygen storage capacity in autothermal reforming of methane over Rh/Ce0,45Zr0,45RE0,1 catalysts (RE = La, Pr, Nd, Sm, Eu, Gd, Tb) // Catalysis Communications. 2009. Vol. 10. Р. 1192—1195.

17. Либерман Е.Ю., Малютин А.В., Клеусов Б.С., Михайличенко А.И., Конькова Т.В. Наноструктурированные катализаторы для очистки газовых сред от монооксида углерода// Экология и промышленность России. 2012. № 7. С. 25—27.

18. Шабанова Н.А., Попов В.В., Саркисов П.Д. Химия и технология нанодисперсных оксидов. М.: ИКЦ «Академкнига», 2007. С. 88.

19. Arai S., Muto S., Murai J., Sasaki T., Ukyo Y. and et. Valence Change of Cations in Ceria-Zirconia Solid Solution Associated with Redox Reactions Studied with Electron Energy-Loss Spectroscopy // Materials Transactions. 2004. Vol. 45. № 10. P. 2951—2955.

20. Rojas T.C., Ocana M. Uniform nanoparticles of Pr(III)/Ceria solid solutions prepared by homogeneous precipitation // Scripta Naterialia. 2002. Vol. 46. Р. 655—660. http://www.webelements.com

21. Гасымова Г.А., Иванова О.С., Баранчиков А.Е., Щербаков А.Б., Иванов В.К., Третьяков Ю.Д. Синтез водных золей нанокристаллического диоксида церия, допированного гадолинием // Наносистемы: физика, химия, математика. 2011. № 2. С. 113—120.