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利用程序升温氧化、差热分析、热重等方法考察了两种长链烷烃脱氢工业铂锡催化剂表面的积炭特征。结果表明催化剂表面的积炭不仅沉积在活性金属表面,而且也沉积在载体氧化铝的表面;金属表面的积炭具有较高的氢/炭比,约在450℃以下就可基本被烧除,而载体表面的积炭则是氢/炭比例较低、石墨化程度较高的炭,在450℃以上才开始燃烧。此外,金属表面的积炭对催化剂的脱氢性能有较大的影响,而载体表面的积炭对催化剂的脱氢活性影响不大。
The characteristics of carbon deposition on the surface of two long-chain alkane dehydrogenation platinum-tin catalysts were investigated by temperature-programmed oxidation, differential thermal analysis and thermogravimetry. The results show that the coke deposition on the catalyst surface is not only deposited on the surface of the active metal, but also deposited on the surface of the carrier alumina. The coke deposition on the metal surface has a high hydrogen / carbon ratio and can be almost ablated at about 450 ℃. On the other hand, the coke on the surface of the carrier is a carbon with a lower hydrogen / carbon ratio and a higher degree of graphitization, which begins to burn at a temperature above 450 ° C. In addition, the carbon deposition on the metal surface has a greater impact on the dehydrogenation performance of the catalyst, while the carbon deposition on the surface of the support has little effect on the dehydrogenation activity of the catalyst.