摘要：

A new type of Re/sub 2/O/sub 7//Al/sub 2/O/sub 3/ catalyst has been prepared. Its optical properties, which are important in view of the experimental problems of in situ infrared spectroscopy of solid catalysts, are excellent. The carrier surface is completely covered with a monolayer of Re/sub 2/O/sub 7/. The spectrum of the calcined catalyst is characterized by hydroxyl bands at ca. 3500, 3640, and 3700 cm/sup -1/ and by bands at 2000 and 1980 cm/sup -1/. At room temperature water is absorbed mainly associatively; its infrared spectrum is characterized by a very broad band centered around 3100 cm/sup -1/. At higher temperatures dissociative adsorption occurs, giving two types of hydroxyl groups characterized by infrared bands at 3500 and 3640 cm/sup -1/. On reduction with hydrogen at 773/sup 0/K a considerable amount of the Re/sub 2/O/sub 7/ is reduced to metal; by x-ray spectroscopy rhenium metal crystals have been found. On subsequent oxidation with oxygen at 823/sup 0/K the rhenium atoms are spread over the surface, reforming a monolayer of Re/sub 2/O/sub 7/.

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