| Abstract: | The support effect on the low-temperature propane combustion over platinum catalysts was investigated by kinetic study. The catalytic activity of supported platinum catalysts varied with the support material, and Pt/SiO2–Al2O3 showed much higher activity than Pt/ZrO2, as already reported. The reaction order for oxygen was negative and that for propane was positive. The reaction order for propane and oxygen also greatly depended on the support material: Pt/ZrO2 gave anomalous reaction orders, i.e., –2.9 for oxygen and 3.4 for propane. Further, oxidized Pt/ZrO2 showed a long-term change of the catalytic activity with time-on-stream, compared with oxidized Pt/SiO2–Al2O3. From these results, it was concluded that high catalytic activity of platinum on acidic support is attributed to high ability to maintain the metallic state of platinum with high oxidation-resistance and high reducibility of platinum oxide. |
