以水热法合成的水合氧化锆为载体的Pt／WO3-ZrO2上的正己烷异构化

n-Hexane Isomerization by Pt/WO_3-ZrO_2 Using Hydrothermally Synthesiz ed Hydrous Zirconia as Support

通过水热法合成了一系列水合氧化锆,以之为载体采用浸渍法制备了Pt/WO3-ZrO2催化剂,考察了氢氧化锆的水热温度对Pt/WO3-ZrO2异构化活性的影响.通过X射线衍射、NH3程序升温脱附及H2程序升温还原表征了样品的晶相结构、酸性及还原性能.结果表明,水合氧化锆及以此为载体的催化剂的晶相结构均随着氢氧化锆水热温度的变化而变化,水热温度升高,四方相氧化锆比例下降.具有一定晶相结构的水合氧化锆为载体的催化剂具有较无定形氢氧化锆为载体的催化剂更多的强酸中心和更高的异构化催化活性.高的异构化活性可能与催化剂上更多的强酸中心有关。

A series of hydrous zirconia samples were prepared by the hydrothermal method, and the Pt/WO3-ZrO2 catalyst was prepared by impregnation. The effects of hydrothermal temperature of Zr（OH）4 on the isomerization activity of the catalyst was investigated. The crystalline structure, acidity, and reduction properties of the catalyst were characterized by X-ray diffraction, NH3 temperature-programmed desorption, and H2 temperature-programmed reduction, respectively. The results indicated that the crystalline structure of hydrous zirconia and the catalyst varied with the hydrothermal temperature, and the increase of hydrothermal temperature reduced the fraction of tetragonal zirconia. Strong acid sites on the catalyst and the isomerization activity increased with the crystallization of Zr（OH）4. It was proposed that the higher isomerization activity may he related to the existence of large numbers of strong acid sites.