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
