1. 1. 2. 3. 4. © Kinetic Modeling Of CO Oxidation On Pt/CeO2 In A Gradientless Reactor Shalabi, MA; Harji, BH; Kenney, CN JOHN WILEY SONS LTD, JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY; pp: 317-324; Vol: 65 King Fahd University of Petroleum & Minerals http://www.kfupm.edu.sa Summary Cerium oxide is a major additive in three-way catalysts used in emission control of automobile exhaust. Pt/CeO2 was studied in order to better understand the role of ceria in promoting CO oxidation reaction. The kinetics of carbon monoxide oxidation on Pt/cerium oxide catalyst, was studied over the temperature range 100-170 degrees C. Steady state kinetic measurements of CO oxidation were obtained in a computer controlled micro-CSTR reactor. Activation energies were reported to vary between 39.5 and 512 kJ mol(-1). At low concentrations of either reactant (CO, O-2) and total conversion, the catalyst exhibited multiple steady states, similar to the multiplicity behavior of Pt/Al2O3. The total conversion was reached at 120 degrees C. In comparison, the total conversion at low reactant concentrations was reached at a temperature of 148 degrees C for the alumina-supported catalyst. Langmuir- Hinshelwood mechanisms gave a good fit to the data. However, no single rate expression could effectively describe the CO oxidation data over the whole concentration in the product of the CSTR reactor. The facts gathered indicate that oxygen adsorbed on interfacial Pt/Ce sites and ceria lattice oxygen provides oxygen for CO oxidation. Cerium oxide has been found to lower CO oxidation activation energy, enhance reaction activity and tends to suppress the usual CO inhibition effect. References: BARRAULT J, 1990, APPL CATAL, V58, P255 BECK DD, 1989, CHEM PHYS LETT, V159, P207 CUTLIP MB, 1978, ACS SYM SER, V65, P475 DANIEL DW, 1988, J PHYS CHEM-US, V92, P3891 Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa

2. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. © DENOTTER GJ, 1978, J CATAL, V53, P116 ENGLER B, 1989, APPL CATAL, V48, P71 GAUGUIN R, 1975, ADV CHEM SER, V143, P147 HAALAND DM, 1982, J CATAL, V76, P450 HAWKINS CJ, 1978, THESIS U CAMBRIDGE HERSKOWITZ M, 1983, CAN J CHEM ENG, V61, P194 HERZ RK, 1985, J CATAL, V94, P166 HINDIN SG, 1975, 3870455, US HOLLIDAY R, 1981, THESIS U CAMBRIDGE JIN T, 1987, J PHYS CHEM-US, V91, P3310 JIN T, 1987, J PHYS CHEM-US, V91, P5931 KIM G, 1982, IND ENG CHEM PROD RD, V21, P267 KUMMER JT, 1976, 760143 SE LINDSTROM TH, 1984, SURF SCI, V146, P569 LOOF P, 1989, J CATAL, V118, P339 LOOF P, 1991, J CATAL, V130, P181 MIKUS O, 1981, J CATAL, V69, P140 NUNAN JG, 1992, J CATAL, V133, P209 OH SH, 1986, J CATAL, V100, P360 OH SH, 1988, J CATAL, V112, P543 PANDE NK, 1986, J CATAL, V97, P137 SASS AS, 1985, KINET KATAL, V26, P1411 SASS AS, 1986, KINET KATAL, V27, P894 SCHLATTER JC, 1980, IND ENG CHEM PROD RD, V19, P288 SCHUBERT PJ, 1987, 61 ACS M ANN ARB SHALABI MA, 1979, IND ENG CHEM PROC DD, V18, P474 SHYU JZ, 1988, J CATAL, V114, P23 SHYU JZ, 1989, J CATAL, V115, P16 SU EC, 1985, APPL CATAL, V17, P75 SUMMERS JC, 1979, J CATAL, V58, P131 VORTRUBA J, 1976, CHEM ENG SCI, V31, P971 YAO HC, 1977, J CATAL, V50, P407 YAO HC, 1984, J CATAL, V86, P254 YAO YFY, 1979, 6 N AM CAT SOC M CHI ZAFIRIS CS, 1992, AICHE ANN M MIAM, P1 For pre-prints please write to: abstracts@kfupm.edu.sa Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa