Abstract: Pt/SO42?/ZrO2-Al2O3 (PSZA) catalyst was prepared by impregnating SO42?/ZrO2-Al2O3 with H2PtCl6. The effect of activation condition on n-hexane isomerization activity of PSZA catalyst was investigated. The catalyst was characterized by temperature-programmed oxidation (TPO-MS), temperature-programmed nitrogen treatment (TPN-MS) and temperature-programmed reduction (TPR-MS). The n-hexane isomerization activity of the catalyst was evaluated in a continuous flow fixed bed reactor. The experiment results showed that the conversion of n-hexane over PSZA was about 85% when it was activated in air at the temperature ranging from 200 ℃ to 500 ℃. However, the catalyst hardly possessed the isomerization activity when PSZA was activated in nitrogen at above 300 ℃. The reduction pretreatment at a high temperature above 300 ℃ led to the great decrease in catalytic activity. It was proposed that the role of activation in air at a high temperature was not only removal of water on the catalyst, but also re-oxidation of catalyst surface, which led to high catalytic activity. However, the pre-treatment in hydrogen gas at a high temperature led to the loss of sulfur species over PSZA, resulting in significant decrease in catalytic activity. The suitable activation condition was as follows：pretreatment in air at the temperature ranging from 300 ℃ to 500 ℃ and reduction in hydrogen gas at 250 ℃.

Key words: activation condition, Pt, SO42?/ZrO2-Al2O3, n-hexane, isomerization

摘要： 采用浸渍法制备了Pt改性的Pt/SO42?/ZrO2-Al2O3（PSZA）催化剂，考察了活化条件对PSZA催化剂正己烷异构化活性的影响，采用程序升温氧化（TPO-MS）、氮气-程序升温处理（TPN-MS）、程序升温还原（TPR-MS）对催化剂进行表征。异构化反应在连续流动的固定床微型反应器中进行。结果表明，200 ℃以上的高温氮气中活化预处理后的PSZA几乎没有异构化活性；空气气氛中、200～500 ℃高温条件下活化预处理的PSZA表现出了较高的异构化活性,正己烷初始转化率均在85%以上。在高于300 ℃的氢气中活化预处理，PSZA表现出较低的异构化活性。空气气氛中预处理除脱水之外，由于氧气的存在对催化剂的表面起到再氧化作用，导致高的异构化活性。氢气气氛中高温活化预处理导致了PSZA上硫物种的损失，进而引起异构化活性的下降。PSZA适宜的预处理条件为：空气气氛、300～500 ℃活化，250 ℃氢气中还原。

关键词: 活化条件, 铂, SO42?/ZrO2-Al2O3, 正己烷, 异构化