关键词: 透射电子显微术, 铂, 红外分光光度法, 催化剂, 沸石, 程序升温脱附, 异丙醇, 相互作用, 外里叶变换, 探针反应法

A new in situ IR cell (made of metal and suitable for catalysis research) is described. The Pt dispersed on acidic NH4L zeolite exhibits "electron deficiency" and does not show obvious dehydrogenation activity in the iso-PrOH decomposition reaction. However, it enhances the conversion of iso-PrOH to form H2O and propene through the protection for acid sites on the zeolite against deactivation by carbonaceous overlayers. However, Pt on KL basic zeolite exhibits some electron rich and high dehydrogenation activity in iso-PrOH decomposition Also, Pt/KL is very sensitive to thiophene poisoning of these reactions. During pretreatment and reaction, the Pt on a mixture of (Pt/KL+NH4L) migrates from KL to NH4L resulting in catalytic properties of the mixture similar to those of Pt/NH4L in the decomposition of iso-PrOH. There is an obvious interaction between Pt and L zeolites. The supported Pt can become "electron deficient" more easily than it can become "elecronic rich" which means that the interaction of Pt with acid sites is stronger than with basic sites; this is because of the metallicity of Pt which can be an electron donor easily, but has more difficulty in being an electron acceptor.

Key words: TRANSMISSION ELECTRON MICROSCOPY, PLATINUM, INFRARED SPECTROPHOTOMETRY, CATALYST, ZEOLITE, TEMPERATURE PROGRAMMING DESORPTION, ISOPROPANOL, INTERACTIONS