Comparison of the Activity of Pt/Al2O3 and of Pt/CeO2/Al2O3 to CO Oxidation Reaction

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Akkarat Wongkaew*

Abstract

The activity of platinum promoted with ceria over alumina to CO oxidantion reaction was investigated over temperature range of 100°C to 200°C. The results indicated that the presence of ceria doped in alumina as a support dramatically enhanced the activity of platinum over pure alumina. This can be observed from T1/2 of each catalyst. From the experiments, T1/2 of the 5% Pt/Al2O3 was 170°C while T1/2 of the 5%Pt/15%CeO2/Al2/O3 was 145°C. This behavior can be explained from the FTIR results. Under the condition that 1%CO in He was purged over the 5%Pt/15CeO2/Al2/O3, CO2 was observed. This implied that the formation of CO2 occurred from reaction between CO molecules and O atoms from ceria lattice. These catalysts were tested under different oxygen concentrations. The results showed that the CO conversion for the 5%Pt/15%CeO2/Al2/O3 at a range of 100°C to 150°C was not different under 1%O2 and 2%O2 respectively. On the other hand, for the 5% Pt/Al2O3, CO conversion at the studied temperatures incredibly increased with the increasing of O2  concentration from 1% O2 to 2%O2. Therefore, the improvement of the performance of platinum over alumina to CO oxidation at temperatures less than 160°C can be done by doping with a little amount of ceria.


Keywords: CO oxidation, Platinum over alumina, sol gel method, ceria, oxygen storage properties


Corresponding author: E-mail: akkarat@buu.ac.th

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Original Research Articles

References

[1] Bourane, A., Derrouiche, S., and Bianchi, D. 2004 Impact of Pt Dispersion on the Steps of CO Oxidation by O2 Over Pt/Al2/O3, Journal of Catalysis, 2, 255-297.
[2] Costello, C.K., Kung, M.C., Oh, H-S., Wang, Y., and Kung, H.H. 2002, Nature of the Active Site for CO Oxidation on Highly Active Au/γ-Al2O3, Applied Catalysis A: General, 2(232), 159-168.
[3] Ruth, K., Hayes, M., Burch, R., Tsubota, S., and Haruta, M. 2000 The Effect of SO2 on the Oxidation of CO and Propane on Supported Pt and Au Catalysts, Applied Catalysis B: Environmental, 24, L133-L138.
[4] Gulari, E., Guldur, C., Srivannavit, S., and Osuwan, S. 1999 CO Oxidation by Silver Cobalt Composite Oxide, Applied Catalysis A: General, 182, 147-163.
[5] Kobayashi, M., and Takegami, H. 1984 Heterogeneity of a Silver Surface Used in the Oxidation of Carbon Monoxide, J. Chem. Soc., Faraday Trans. 1, 80, 1221-1231.
[6] Holmgren, A., Duprez., D., and Andersson, B. 1999 A Model of Oxygen Transport in Pt/Ceria Catalysts from Isotope Exchange, Journal of Catalysis, 182, 441-448.
[7] Rogemond, E., Frety, R., Perrichon, V., Primet, M., Salasc, S., Chevrier, C., Gauthier, C., and Mathis, F. 1997 Preparation of Alumina-Supported Ceria II. Measurement of Ceria Surface Area after Impregnation with Platinum and Rhodium, Journal of Catalysis, 169, 120-131.
[8] Yoldas, G.E. 1975 Preparation of Solid Oxide via Alkoxide by Sol-Gel Method, Ceramic Bulletin, 54, 298-301.