| 초록 |
The activation of CH4 over monometallic PGM catalysts normally requires high reaction temperatures above 500 ℃. Moreover, modern engines emit lower temperature of exhaust gases. This also makes the CH4 oxidation challengeable since the intrinsic activity of PGM catalysts is strongly sensitive to the O2 concentration. In this study, we prepared seven Pd-Pt catalysts supported on γ-alumina as a function of Pd:Pt ratio while fixing a total number of Pd, Pt metal (350 μmol/g.cat). The CH4 oxidation was tested with respect to the O2/CH4 ratio varying O2 concentration. The catalysts were also tested under the dry and wet feed to characterize the inhibition of water. The Pd-rich catalysts represented the light off curves at lower temperature region at around 300 ℃. The inhibition of water on the CH4 oxidation was more pronounced over the Pd-only catalysts, while the Pd:Pt-3:1 catalysts showed a superior overall activity against the presence of hydroxyl group on catalytic surfaces. The beneficial effect of Pt presented in the bimetallic Pd/Pd catalyst may be attributed to the increased adsorption stability for methane under the wet condition. |
